Air Pollution in India | Environment Notes 2025

Introduction

Air pollution in India has become one of the gravest environmental challenges confronting India. The deteriorating air quality in both urban and rural areas is contributing significantly to respiratory diseases, environmental degradation, and reduced quality of life. Rapid industrialization, vehicular emissions, construction activities, and agricultural practices like stubble burning have worsened the situation.

Status of Air Pollution in India

Global Rankings and Reports

• According to the IQAir Air Quality Report (Swiss-based organization):
  • 22 out of the 30 most polluted cities in the world are in India.
  • 14 out of the top 15 most polluted cities globally are Indian cities.
  • Ghaziabad, in the National Capital Region (NCR), was ranked as the second most polluted city in the world.

State of Global Air Report 2020

• India recorded the highest annual average exposure to PM2.5 concentration in 2019.
• For the last decade, India has had the worst PM2.5 levels globally.

World Air Quality Report 2021

• In 2021, India had 11 out of the 15 most polluted cities in Central and South Asia.

Major Pollutants in India

Pollutant	Sources	Health Effects
PM2.5 and PM10	Vehicular emissions, construction dust, industrial emissions, biomass burning	Lung diseases, heart problems, asthma
SO₂ and NOₓ	Power plants, diesel engines, industrial combustion	Respiratory irritation, acid rain formation
CO (Carbon Monoxide)	Incomplete combustion of fossil fuels	Reduces oxygen delivery in the body, especially dangerous in enclosed spaces
O₃ (Ground-level Ozone)	Secondary pollutant formed from NOₓ and VOCs in sunlight	Eye irritation, decreased lung function
Volatile Organic Compounds (VOCs)	Solvents, paints, vehicle exhaust	Some are carcinogenic and contribute to smog
Lead and Heavy Metals	Battery recycling, industrial discharge	Neurological disorders, especially in children

Government Interventions to Combat Air Pollution in India

1. National Air Quality Monitoring Programme (NAMP)

Introduction

The National Air Quality Monitoring Programme (NAMP) is India’s flagship scheme for ambient air quality monitoring. It is executed by the Central Pollution Control Board (CPCB) in collaboration with State Pollution Control Boards (SPCBs), Pollution Control Committees (PCCs), and other recognized agencies across the country.

As of 19th November 2024, the NAMP network comprises:

• 966 operating stations
• Spread over 419 cities/towns
• Across 28 States and 7 Union Territories

Objectives of NAMP

NAMP is designed with a scientific and regulatory framework to guide India’s air quality management strategies. The key objectives include:

1. To determine status and trends of ambient air quality across various urban and rural locations.
2. To evaluate compliance with the National Ambient Air Quality Standards (NAAQS).
3. To identify Non-Attainment Cities — those cities where air quality consistently violates prescribed standards.
4. To provide data for policy formulation and develop preventive/corrective strategies to reduce air pollution.
5. To understand the natural cleansing mechanisms in the environment such as:
   • Pollution dilution
   • Dispersion by wind
   • Dry deposition
   • Precipitation
   • Chemical transformation of pollutants

Pollutants Monitored under NAMP

Under NAMP, four critical air pollutants are regularly monitored at all designated stations:

Pollutant	Details
Sulphur Dioxide (SO₂)	Emitted from fossil fuel combustion; precursor to acid rain
Oxides of Nitrogen (NO₂)	Mainly from vehicular and thermal power emissions; causes respiratory ailments
Respirable Suspended Particulate Matter (RSPM/PM10)	Particles ≤ 10 μm; penetrate lungs and cause bronchial issues
Fine Particulate Matter (PM2.5)	Particles ≤ 2.5 μm; deeply penetrate lung alveoli and enter bloodstream

These pollutants were selected based on their prevalence, health impacts, and regulatory importance under the Air (Prevention and Control of Pollution) Act, 1981.

Meteorological Parameters Also Measured

To better understand pollutant behavior and dispersion, meteorological parameters are monitored alongside pollutant levels:

• Wind Speed and Wind Direction
• Temperature
• Relative Humidity (RH)

These factors influence the spread and transformation of pollutants and are crucial for air quality modelling.

Monitoring Frequency and Methodology

Parameter	Sampling Duration	Frequency
Gaseous Pollutants (SO₂, NO₂)	Every 4 hours	Twice a week
PM10	Every 8 hours	Twice a week
PM2.5	24-hour composite sampling	Twice a week

This gives a total of 104 observations per year per station, providing a statistically significant dataset for long-term analysis.

Operational Framework

• NAMP is operated by:
  • CPCB (Central Pollution Control Board)
  • SPCBs (State Pollution Control Boards)
  • PCCs (Pollution Control Committees)
  • Other Authorized Monitoring Agencies
• CPCB’s Role:
  • Coordinates with state and regional agencies
  • Ensures data standardization and quality control
  • Provides technical and financial assistance
  • Facilitates uniform sampling and reporting methods

Limitations and Data Usage

Due to the involvement of multiple personnel and agencies, NAMP data may have:

• Variability due to equipment performance or human error
• Biases introduced during sampling or analysis
• Gaps in data continuity in certain remote or under-equipped areas

Thus, the data is considered indicative, not absolute, and is primarily used for policy guidance and trend analysis rather than real-time air quality alerts.

2. National Air Quality Index (AQI) – India

Introduction

The Air Quality Index (AQI) is a standardized tool developed to effectively communicate the current air quality status in a simplified, easy-to-understand format. It converts complex, real-time pollution data into a single numerical value, color code, and descriptive category. The AQI helps the general public, policymakers, and local administrations understand the quality of air and take preventive or corrective actions.

The AQI is implemented by the Central Pollution Control Board (CPCB) under the Ministry of Environment, Forest and Climate Change (MoEFCC).

Purpose of AQI

• Public Awareness: Makes pollution data accessible to non-technical users.
• Health Advisory: Connects pollutant concentration to public health impact.
• Policy Monitoring: Enables daily tracking of city-level air pollution.
• Pollution Alerts: Helps in issuing warnings and emergency actions (e.g., GRAP in Delhi).

Components of AQI

The AQI is calculated using eight pollutants, based on their ambient concentration and associated short-term health impacts:

Pollutant	Full Name	Type	Monitoring Time
PM10	Particulate Matter ≤10 µm	Particulate	24-hourly average
PM2.5	Particulate Matter ≤2.5 µm	Particulate	24-hourly average
NO₂	Nitrogen Dioxide	Gaseous	24-hourly average
SO₂	Sulphur Dioxide	Gaseous	24-hourly average
CO	Carbon Monoxide	Gaseous	8-hourly average
O₃	Ozone	Gaseous	8-hourly average
NH₃	Ammonia	Gaseous	24-hourly average
Pb	Lead	Heavy Metal	24-hourly average

Each pollutant is assigned a sub-index value based on its concentration. The highest sub-index among all pollutants becomes the overall AQI value.

How AQI is Calculated

• Each pollutant’s ambient concentration is measured.
• A sub-index for each pollutant is calculated using a linear function between the concentration and health breakpoints.

Example (for PM2.5):

• 31 µg/m³ → Sub-index = 51
• 60 µg/m³ → Sub-index = 100
• 45 µg/m³ → Sub-index = 75
• The worst (highest) sub-index among the eight pollutants determines the final AQI category for the location.

AQI Categories and Health Breakpoints

AQI Category	AQI Value	PM10	PM2.5	NO₂	O₃	CO (mg/m³)	SO₂	NH₃	Pb
Good	0 – 50	0 – 50	0 – 30	0 – 40	0 – 50	0 – 1.0	0 – 40	0 – 200	0 – 0.5
Satisfactory	51 – 100	51–100	31–60	41–80	51–100	1.1–2.0	41–80	201–400	0.5–1.0
Moderately Polluted	101 – 200	101–250	61–90	81–180	101–168	2.1–10	81–380	401–800	1.1–2.0
Poor	201 – 300	251–350	91–120	181–280	169–208	10–17	381–800	801–1200	2.1–3.0
Very Poor	301 – 400	351–430	121–250	281–400	209–748	17–34	801–1600	1200–1800	3.1–3.5
Severe	401 – 500	430+	250+	400+	748+	34+	1600+	1800+	3.5+

Note:

• PM10, PM2.5, NO₂, SO₂, NH₃, and Pb: 24-hourly average values.
• CO and O₃: 8-hourly average values.

Color Codes for AQI Categories

Category	Color	Health Advisory
Good	Dark Green	Minimal or no impact
Satisfactory	Light Green	Minor breathing discomfort to sensitive people
Moderately Polluted	Yellow	Discomfort to people with heart/lung disease, children, elderly
Poor	Orange	Breathing discomfort on prolonged exposure
Very Poor	Red	Respiratory illness on prolonged exposure
Severe	Dark Maroon	Serious respiratory effects even on healthy people; emergency action may be needed

Significance of AQI in Policy and Public Health

• Real-Time Data: AQI is displayed publicly on platforms like SAFAR, AQICN, CPCB, etc.
• Basis for Action Plans: Used for implementing Graded Response Action Plan (GRAP) in Delhi and other NCR areas.
• Public Alerts: School closures, construction bans, and traffic restrictions are based on AQI thresholds.
• Compliance with NAAQS: Helps in evaluating whether air quality complies with National Ambient Air Quality Standards (set by CPCB).
• Input to Global Reports: India’s AQI data contributes to reports by WHO, UNEP, and other international agencies.

3. Graded Response Action Plan (GRAP) – Delhi-NCR

Introduction

The Graded Response Action Plan (GRAP) is an emergency response framework for combating air pollution in the Delhi-National Capital Region (NCR). It is a dynamic, tiered intervention system that prescribes pre-emptive and corrective measures based on real-time pollution levels, specifically PM10 and PM2.5 concentrations.

GRAP has become the backbone of Delhi’s air pollution management strategy, particularly during winter months when air quality tends to deteriorate to hazardous levels.

Origin and Legal Framework

• Mandated by: Supreme Court of India (Order dated December 2016)
• Prepared by: Ministry of Environment, Forest and Climate Change (MoEFCC)
• Implementing Agency (until 2021): Environmental Pollution (Prevention and Control) Authority (EPCA)
• Current Implementing Body (from 2021): Commission for Air Quality Management (CAQM)

Objectives of GRA

• Prevent further deterioration of air quality
• Provide a structured escalation mechanism
• Synchronize actions among multiple state and central agencies
• Act as a short-term emergency plan, complementing long-term pollution control strategies like NCAP

Key Features of GRAP

• Focuses on PM2.5 and PM10 as trigger parameters
• Actions graded into four pollution categories
• Each category has pre-decided interventions
• Measures are mandatory and legally enforceable
• Area of implementation: Entire Delhi-NCR region

Categorization of Pollution Levels and Action Measures

Pollution Category	PM2.5 Level (µg/m³)	PM10 Level (µg/m³)	Key Interventions
Moderate to Poor	61 – 120	101 – 350	– Enforce thermal plant controls – Ban on firecrackers – Stop garbage burning – Mechanized road sweeping
Very Poor	121 – 250	351 – 430	– Ban diesel gensets (non-emergency) – Enhance bus/metro frequency – Ban coal/firewood in eateries
Severe	>250	>430	– Sprinkle water & clean roads – Close brick kilns, stone crushers, hot mix plants – Shut Badarpur power plant – Concessions for off-peak travel
Severe+ / Emergency	≥300 (for 48 hrs)	≥500 (for 48 hrs)	– Ban entry of diesel trucks (except essentials) – Ban construction activities – Implement odd-even vehicle rule – Close schools

Implementation and Monitoring

• Real-time monitoring is done via the National Air Quality Index (AQI) and SAFAR.
• Once air quality reaches a predefined threshold, the Commission for Air Quality Management (CAQM) triggers the appropriate response level.
• Agencies involved: CPCB, DPCC, Delhi Government, Urban Local Bodies, Delhi Metro Rail Corporation (DMRC), Delhi Transport Corporation (DTC), NDMC, MCDs, etc.

Recent Enforcement Examples

• Winter 2023–24: GRAP Stage III was enforced multiple times in Delhi after PM2.5 crossed 250 µg/m³ for consecutive days.
• Odd-Even Scheme: Implemented during Severe+ category periods, banning alternate-day vehicle use.
• Diesel Genset Ban: Enforced in Very Poor and higher categories, except for emergency services like hospitals.

Effectiveness and Criticisms

Positive Outcomes:

• Reduces sudden spikes in PM levels.
• Improves coordination across NCR states (Haryana, UP, Rajasthan, Delhi).
• Publicly visible interventions raise awareness.

Challenges:

• Focus is reactive, not preventive.
• Enforcement is often lax in neighboring NCR towns.
• No provisions for long-term infrastructure upgrades.
• Reliant on weather patterns (e.g., wind dispersion, rain).

GRAP vs NCAP

Aspect	GRAP	NCAP
Type	Emergency response	Long-term strategy
Trigger	Real-time AQI and PM levels	Historical and average AQI levels
Area	Delhi-NCR	132 Non-attainment cities (pan-India)
Timeframe	Seasonal (mainly winter)	Continuous
Focus	Immediate action	Emission reduction, infrastructure

4. National Clean Air Programme (NCAP)

The National Clean Air Programme (NCAP) is a landmark initiative launched in January 2019 by the Ministry of Environment, Forest and Climate Change (MoEF&CC), Government of India. This programme was introduced to comprehensively address the critical issue of air pollution, which poses severe health, environmental, and socio-economic challenges across India. Unlike previous isolated measures, NCAP represents a coordinated and systematic approach, bringing together multiple ministries, state governments, urban bodies, industries, and local communities.

NCAP specifically targets air quality improvement at three interconnected levels—city, regional, and national. More than 100 cities, termed non-attainment cities, have been identified as priority targets. These cities consistently fail to meet the National Ambient Air Quality Standards (NAAQS), indicating persistent air quality issues requiring focused interventions.

Primary Goal of NCAP

The fundamental aim of NCAP is clearly defined: to achieve the prescribed annual average ambient air quality standards throughout India within a stipulated long-term timeframe. Achieving these standards is essential for reducing health risks, enhancing environmental sustainability, and improving the overall quality of urban life.

NCAP’s Specific Targets

NCAP sets a measurable target to drive tangible outcomes:

• Reduction of PM10 levels by up to 40% by the fiscal year 2025–26, taking the pollution levels of 2019–20 as the baseline.
• Alternatively, reaching the prescribed national ambient air quality standard for PM10 (60 µg/m³) within the stipulated period.

These targets align closely with successful international experiences in air quality management. For instance, cities like Beijing and Seoul demonstrated 35–40% reductions in PM2.5 within five years of stringent action. Similarly, cities such as Santiago (Chile) and Mexico City achieved impressive long-term reductions of around 73% and 61% respectively in particulate matter over two decades. Such global benchmarks highlight that substantial improvements are achievable with consistent and coordinated action.

Key Objectives of NCAP

The programme has outlined specific, actionable, and measurable objectives:

• Stringent Implementation of Mitigation Measures
  NCAP mandates rigorous enforcement of measures for the prevention, control, and abatement of air pollution. These include stricter regulations on vehicular emissions, industrial pollutants, dust management protocols, waste management, and green construction practices.
• Strengthening Air Quality Monitoring Infrastructure
  It emphasizes augmenting and evolving a nationwide network of air quality monitoring stations. This infrastructure upgrade aims to ensure reliable data availability, transparency, and accuracy for evidence-based policy formulation.
• Public Awareness and Capacity Building
  Enhancing public awareness about air pollution through educational programmes, mass media outreach, and community-level campaigns is a core NCAP strategy. Capacity-building initiatives also target local administrators, industry personnel, and public representatives, equipping them with essential knowledge and skills for effective implementation.

Tenure and Implementation Timeline

Initially, NCAP was launched as a five-year mid-term action plan (2019–2024). However, global experiences and detailed national assessments suggest that significant air-quality improvements usually manifest clearly over a longer timeframe (20–25 years). Therefore, NCAP is designed to extend beyond its initial phase following mid-term assessments and performance reviews, potentially spanning two decades to yield enduring results.

Financial Arrangement under NCAP

Robust financial backing underscores NCAP’s ambitious vision:

• Since its inception, Rs. 1615.48 crores have been allocated specifically to non-attainment cities for air quality interventions (FY 2019–20 onwards).
• An additional Rs. 11020.55 crores have been disbursed under the 15th Finance Commission Grants to 42 urban agglomerations with populations exceeding one million (FY 2020–21 onwards).
• The financial strategy also includes leveraging resources from existing central government schemes such as:
  • Swachh Bharat Mission (Urban)
  • Atal Mission for Rejuvenation and Urban Transformation (AMRUT)
  • Smart City Mission
  • Sustainable Alternative Towards Affordable Transportation (SATAT)
  • Faster Adoption and Manufacturing of Electric Vehicles (FAME-II)

Funding under NCAP and the 15th Finance Commission grants is provided as performance-based supplemental assistance, specifically addressing funding gaps identified within City Action Plans (CAPs) developed by local authorities.

Strategic and Multi-dimensional Approach

NCAP is characterized by its comprehensive, collaborative, and flexible approach:

• Collaborative Cross-sectoral Coordination:
  It promotes active collaboration between central ministries (Environment, Road Transport, Power, Petroleum, Renewable Energy, Heavy Industry, Urban Affairs, Agriculture, Health, Finance), state governments, urban local bodies, and citizen groups.
• Integration with National Climate Initiatives:
  NCAP aligns closely with existing programmes like the National Action Plan on Climate Change (NAPCC), particularly leveraging initiatives under:
  • National Solar Mission
  • National Mission for Enhanced Energy Efficiency
  • National Mission on Sustainable Habitat
  • National Mission for a Green India
  • National Mission for Sustainable Agriculture
    This integration ensures co-benefits in both air pollution reduction and climate change mitigation.
• Leveraging Smart Cities Framework:
  The programme utilizes the Smart Cities Mission framework extensively, especially since 54 of the 130 non-attainment cities are designated Smart Cities. This facilitates the rapid adoption of advanced technological solutions, smart monitoring, and data-driven decision-making processes for air quality management.
• Dynamic Adaptation:
  NCAP remains adaptable and dynamic, continually incorporating new scientific data, technological innovations, and global best practices to enhance its efficacy.

Implementation Framework

• Role of CPCB:
  The Central Pollution Control Board (CPCB) oversees NCAP’s execution under the Air (Prevention and Control of Pollution) Act, 1981, specifically leveraging Section 16(2)(b) for regulatory compliance and enforcement.
• Institutional Mechanisms:
  NCAP is operationalized through structured inter-sectoral committees involving representatives from ministries, NITI Aayog, state pollution control boards, industry experts, academia, and civil society.
• Sectoral Responsibility and Integration:
  Ministries like the Ministry of Road Transport and Highways (MoRTH) (vehicular pollution control), Ministry of Petroleum and Natural Gas, Ministry of Power, and others integrate air-quality goals into their sectoral policies and regulatory frameworks, ensuring comprehensive pollution abatement strategies.
• Regular Monitoring and Evaluation:
  The Apex Committee in MoEF&CC periodically evaluates progress, tracks implementation milestones, and reports annual performance using transparent indicators, thus maintaining accountability and continuous improvement.

Current Status and Early Outcomes

• Out of 130 cities targeted, significant improvements in air quality have already emerged. Specifically, during FY 2023–24, 95 cities reported a clear reduction in PM10 concentrations compared to FY 2017–18 baseline levels. This positive outcome indicates the effectiveness of coordinated interventions under NCAP and provides a strong foundation for sustained progress.

5. Smog Tower 

• In 2019, the Supreme Court directed the Central Pollution Control Board (CPCB) and the Delhi government to come up with a plan to install smog towers to combat air pollution.
  • IIT-Bombay then submitted a proposal for the towers to the CPCB.
  • In January 2020, the Supreme Court directed that two towers should be installed by April as a pilot project.
  • The smog tower at Connaught Place (CP) is the first of these towers. The second tower, being constructed at Anand Vihar in east Delhi with CPCB as the nodal agency, is nearing completion.

What is Smog Tower?

• Smog towers are structures designed to work as large-scale air purifiers.
• They are usually fitted with multiple layers of air filters, which clean the air of pollutants as it passes through them.
• China has the world’s largest smog tower.

Working of the Tower:

• It uses a ‘downdraft air cleaning system’ where polluted air is sucked in at a height of 24 m, and filtered air is released at the bottom of the tower, at a height of about 10 m from the ground.
  
  
  • It is different from the system used in China, where a 60-metre smog tower uses an ‘updraft’ system — air is sucked in from near the ground, and is propelled upwards by heating and convection. Filtered air is released at the top of the tower.

Developed by:

• Tata Projects Limited (TPL) built it with technical support from IIT-Bombay and IIT-Delhi, which will analyse its data.
• National Biofuel Coordination Committee (NBCC) India Ltd is the project management consultant.
• Delhi Pollution Control Committee was in charge of the Project.

What is the Need of Smog tower:

• According to a report by CPCB, an increase of 258% to 335% has been observed in the concentration of PM10 in Delhi since 2009.
• But the most prominent pollutant in Delhi and neighbouring areas is PM2.5
  
  
  • PM2.5 refers to fine particles which penetrate deep into the body and fuel inflammation in the lungs and respiratory tract, leading to risks of cardiovascular and respiratory problems, including a weak immune system.
• Delhi was the most polluted capital city in the world in 2020 for the third consecutive year, according to a report by a Swiss group (released in March 2021) that ranked cities based on their air quality measured in terms of the levels of ultrafine particulate matter (PM 2.5).

Challenges:

• It may provide immediate relief from air pollution in a small area but they are a costly quick-fix measure with no scientific evidence to back their efficacy in the long term.
• The tower could have an impact on the air quality up to 1 km from the tower.
  
  
  • However, the actual impact will be assessed by IIT-Bombay and IIT-Delhi in a two-year pilot study that will also determine how the tower functions under different weather conditions, and how levels of PM2.5 vary with the flow of air.

Other Steps Taken to Tackle the Problem of Pollution in Delhi:

• Subsidy to farmers for buying Turbo Happy Seeder (THS) which is a machine mounted on a tractor that cuts and uproots the stubble, in order to reduce stubble burning.
• The introduction of BS-VI vehicles, push for electric vehicles (EVs), Odd-Even as an emergency measure and construction of the Eastern and Western Peripheral Expressways to reduce vehicular pollution.
• Implementation of the Graded Response Action Plan (GRAP). It is a set of curbs triggered in phases as the air quality deteriorates, which is typical of the October-November period.
• Use of Green Crackers.
• Development of the National Air Quality Index (AQI) for public information under the aegis of the CPCB.

Way Forward

• Since there is no scientific evidence that proves its efficiency, governments should instead address root causes and promote renewable energy to tackle air pollution and reduce emissions.
• It will be really unfortunate if other cities decide to follow suit and set up these expensive, ineffective towers.

Central Pollution Control Board (CPCB)

The Central Pollution Control Board (CPCB) is a statutory body constituted in September 1974 under the provisions of the Water (Prevention and Control of Pollution) Act, 1974. Later, its mandate was expanded to include responsibilities under the Air (Prevention and Control of Pollution) Act, 1981. CPCB serves as the national apex institution for environmental regulation, policy formulation, technical support, and enforcement with regard to pollution control in India.

Functioning under the administrative control of the Ministry of Environment, Forest and Climate Change (MoEF&CC), the CPCB plays a central role in coordinating efforts at the national and state levels to ensure environmental protection through clean air and water governance.

Legal Mandate and Statutory Framework

• Constitutional Base: Statutory body under the Water Act, 1974
• Extended Powers: Entrusted with functions under the Air Act, 1981
• Support Role: Provides technical services and acts as a field formation of MoEF&CC under the Environment (Protection) Act, 1986

Through these Acts, CPCB is empowered to lay down pollution standards, issue directions, conduct inspections, and coordinate the activities of State Pollution Control Boards (SPCBs) and Pollution Control Committees (PCCs) in Union Territories.

Principal Functions of CPCB

Water Pollution Control

• Promotes cleanliness of streams, rivers, and wells through the prevention, control, and abatement of water pollution.
• Advises governments and issues directions for effluent treatment, sewage management, and wastewater discharge control.

Air Pollution Control

• Works to improve ambient air quality across India by framing emission norms, setting National Ambient Air Quality Standards (NAAQS), and monitoring implementation.
• Coordinates national programmes like NAMP (National Air Monitoring Programme) and CAAQM (Continuous Ambient Air Quality Monitoring).

Advisory and Coordination Role

• Advises the Central Government on policies and actions related to air and water pollution control.
• Coordinates with State Pollution Control Boards, offers technical support, and helps resolve disputes between states or SPCBs.

Powers Delegated to Union Territories

• CPCB has delegated its powers under the Water Act, Water Cess Act (1977), and Air Act to regional administrations for effective enforcement in Union Territories.

Standard Development and Regulatory Guidelines

CPCB is the nodal agency responsible for formulating and periodically updating environmental standards across various domains. These standards are adopted nationally and serve as Minimum National Standards (MINAS) to be implemented by states.

Environmental Standards Developed by CPCB Include:

• Ambient Air Quality Standards (PM10, PM2.5, SO₂, NOₓ, O₃, CO, etc.)
• Water Quality Criteria for drinking water, river water, groundwater, and coastal water
• Effluent Discharge Norms for over 250 categories of industries
• Emission Standards under Environment Protection Rules, 1986
• Bio-medical Waste Disposal Standards, including incineration guidelines
• Noise Pollution Standards, including limits for:
  • Diesel engines
  • LPG and CNG generator sets
• Stack Height and Emission Control Guidelines
• Solid Waste Management Protocols

CPCB also publishes:

• COINDS (Comprehensive Industry Documents) for sector-specific pollution profiles
• Guidelines for waste management, industrial siting, and environmental monitoring
• Manuals and Codes of Practice for pollution control technologies and processes

Monitoring and Data Systems

CPCB runs several national-level programmes to generate reliable data on environmental parameters:

• National Ambient Air Quality Monitoring Programme (NAMP)
• Continuous Ambient Air Quality Monitoring System (CAAQMS)
• Water Quality Assessment Authority (WQAA)
• Real-time Effluent and Emission Monitoring (OCEMS) for industries
• National Water Quality Monitoring Programme (NWMP)

These data are essential for assessing pollution trends, identifying hotspots, and formulating data-driven policy interventions.

Role in National Clean Air Programme (NCAP)

Under the Air Act, 1981, especially Section 16(2)(b), CPCB is designated as the national implementing agency for NCAP, responsible for:

• Formulating guidelines for City Action Plans (CAPs) in non-attainment cities
• Monitoring air quality improvements across 130+ non-attainment cities
• Providing financial support and technical assistance
• Reviewing annual performance and emissions data
• Facilitating inter-ministerial and inter-governmental coordination
• Evolving implementation strategies based on scientific and technical updates

Institutional Structure

• Chairman: Appointed by the Central Government (typically an expert in environmental science or public administration)
• Member Secretary: Executive head of CPCB’s functioning
• Members: Includes representatives from various ministries, state boards, industry, NGOs, and academic institutions

CPCB also has zonal offices across different regions to oversee implementation, inspection, and enforcement at the field level.

The Central Pollution Control Board (CPCB) is the backbone of India’s environmental regulatory framework. With its wide-ranging powers under key environmental laws and its central role in initiatives like NCAP, CPCB serves as the principal technical and policy body for ensuring environmental compliance, pollution mitigation, and sustainable development. Its work in standard-setting, pollution monitoring, and inter-agency coordination is crucial for securing a cleaner, healthier future for the nation.

SAFAR (System of Air Quality and Weather Forecasting and Research)

Introduction
SAFAR stands for System of Air Quality and Weather Forecasting and Research. It is India’s first integrated air quality and weather forecasting system designed to provide location-specific, real-time, and forecasted air quality information to the public. SAFAR was launched in 2010 and is developed by the Indian Institute of Tropical Meteorology (IITM), Pune, under the Ministry of Earth Sciences (MoES).

It is one of the most advanced air quality information systems in developing countries and plays a crucial role in public health protection, urban air quality management, and early warning during high-pollution episodes. It also supports India’s commitments under the National Clean Air Programme (NCAP).

Nodal Ministry and Implementing Agency

• Nodal Ministry: Ministry of Earth Sciences (MoES), Government of India
• Developer and Implementing Agency: Indian Institute of Tropical Meteorology (IITM), Pune
• Operational Support: India Meteorological Department (IMD), and Central Pollution Control Board (CPCB)

Objectives of SAFAR

• To provide real-time air quality data and 72-hour advance forecasts for major Indian cities
• To increase public awareness of air pollution levels and associated health risks
• To assist policymakers and pollution control authorities in taking pre-emptive action
• To promote scientific research and policy dialogue on air quality and urban atmospheric chemistry

Key Features of SAFAR

• Multi-Pollutant Monitoring: SAFAR monitors eight critical air pollutants:
  • Particulate Matter (PM2.5 and PM10)
  • Nitrogen Dioxide (NO₂)
  • Sulphur Dioxide (SO₂)
  • Ozone (O₃)
  • Carbon Monoxide (CO)
  • Ammonia (NH₃)
  • Benzene and other Volatile Organic Compounds (VOCs)
• Integrated Weather Forecasting:
  • Temperature
  • Relative humidity
  • Rainfall
  • Wind speed and direction
  • Solar radiation
  • UV Index and Heat Index
• City-specific Air Quality Index (AQI):
  • AQI ranges from 0 (Good) to 500+ (Severe)
  • Health advisories are issued based on AQI levels for sensitive groups (children, elderly, asthmatics)
• Advanced Forecasting Capability:
  • Provides 3-day air quality forecasts using numerical weather prediction (NWP) models
  • Uses data assimilation, satellite inputs, and emission inventories
• User-Friendly Access:
  • Available through web portal (https://safar.tropmet.res.in/)
  • Mobile App (SAFAR-Air)
  • LED display boards in cities
  • Public broadcasts during emergencies

Coverage and Operational Cities (as of 2024)

SAFAR has been operational in major metropolitan cities, including:

• Delhi NCR
• Mumbai
• Pune
• Ahmedabad
• Bengaluru

These cities have a dense network of automated monitoring stations and forecast systems designed specifically for urban and industrial zones.

Scientific and Policy Relevance

• Supports NCAP by providing real-time data and long-term pollution trends
• Enables pollution emergency alerts and health advisories for vulnerable populations
• Facilitates research in urban climate, aerosols, and air chemistry
• Guides urban planning, traffic restrictions, school closures, and firecracker bans during critical episodes like Diwali and winter smog

Achievements and Impact

• First system in India to integrate weather and pollution modeling for city-level predictions
• Enabled real-time decision-making in cities like Delhi during severe air quality events
• Widely used by policymakers, media, hospitals, and the public
• Increased citizen engagement in pollution reduction through awareness

Limitations and Challenges

• Limited to few cities, lacks pan-India coverage
• Requires constant calibration and maintenance
• Needs better integration with state-level air quality planning
• Forecast accuracy can vary depending on meteorological conditions and emission variability

Conclusion

SAFAR is a breakthrough initiative in India’s environmental monitoring landscape. By combining air quality assessment with weather forecasting, it not only provides real-time pollution data but also acts as an early warning system. With growing air quality concerns in Indian cities, expanding and upgrading SAFAR will be critical for evidence-based policy, public health protection, and climate-resilient urban management.

Continuous Ambient Air Quality Monitoring System (CAAQMS)

Introduction
The Continuous Ambient Air Quality Monitoring System (CAAQMS) is a real-time air quality monitoring framework launched in 2010 by the Central Pollution Control Board (CPCB), under the aegis of the Ministry of Environment, Forest and Climate Change (MoEF&CC), Government of India. The system was introduced as a technological upgrade to the existing manual monitoring setup under the National Air Monitoring Programme (NAMP), to address the growing need for real-time, reliable, and scientific data on ambient air quality in urban and industrial areas.

CAAQMS forms a core component of India’s regulatory and planning framework for air pollution management, especially under national programmes such as the National Clean Air Programme (NCAP) launched in 2019.

Nodal Ministry and Implementing Agency

• Nodal Ministry: Ministry of Environment, Forest and Climate Change (MoEF&CC)
• Implementing Agency: Central Pollution Control Board (CPCB)
• Collaborating Agencies: State Pollution Control Boards (SPCBs), Pollution Control Committees (PCCs), Urban Local Bodies (ULBs), and scientific institutions like IITs, TERI, and NEERI

Objectives of CAAQMS

• To capture real-time data on key pollutants including PM10, PM2.5, NO₂, SO₂, CO, O₃, NH₃, and Benzene
• To support scientific policymaking through continuous trend data for pollution episodes and long-term mitigation planning
• To facilitate transparent public information via integration with platforms such as the National Air Quality Index (AQI) and ENVIS
• To assist in emergency response actions during critical pollution events (e.g., smog episodes in Delhi NCR)

Key Features of CAAQMS

• Real-Time Monitoring (24×7):
  CAAQMS uses high-precision instruments to monitor air quality continuously throughout the day, including weekends and holidays, ensuring uninterrupted data flow.
• Multi-Pollutant Tracking:
  Each station is equipped to monitor multiple air pollutants simultaneously including:
  • Particulate Matter (PM10 and PM2.5)
  • Sulphur Dioxide (SO₂)
  • Nitrogen Dioxide (NO₂)
  • Carbon Monoxide (CO)
  • Ozone (O₃)
  • Ammonia (NH₃)
  • Volatile Organic Compounds (VOCs) like Benzene, Toluene, and Xylene
• Meteorological Integration:
  Each station also records meteorological parameters such as temperature, humidity, wind speed, wind direction, and solar radiation, to assist in air pollution dispersion modeling.
• Automated Data Transmission:
  The system is linked to data acquisition and handling systems that automatically transfer data to centralized servers hosted by CPCB and SPCBs.
• Data Availability for Public and Research Use:
  The air quality data from CAAQMS is made available in real-time to the public via platforms like:
  • SAFAR Portal (System of Air Quality and Weather Forecasting and Research)
  • National Air Quality Index (AQI) Dashboard
  • ENVIS network
  • Mobile apps like SAMEER

Coverage and Expansion

• Initial Rollout: Started in 2010 with pilot installations in metro cities including Delhi, Mumbai, Bengaluru, Kolkata, and Chennai
• Current Status (as of 2024):
  • Over 450 CAAQMS stations are operational across 130+ cities
  • Cities under NCAP have been prioritized
  • Non-attainment cities and million-plus urban agglomerations have received targeted funding through 15th Finance Commission Grants

Role in National Clean Air Programme (NCAP)

Under NCAP (2019), real-time data from CAAQMS is used to:

• Assess progress against pollution reduction targets (e.g., 40% reduction in PM10 by 2025–26)
• Guide formulation of City Action Plans (CAPs)
• Facilitate source apportionment studies
• Track the effectiveness of interventions such as vehicular emission control, dust suppression, waste burning prevention, and industrial pollution regulation

CAAQMS serves as the foundational monitoring backbone of NCAP, allowing for evidence-based performance measurement and accountability mechanisms.

Technological Significance

• Advanced Instrumentation: Employs analyzers based on technologies like beta attenuation for PM, chemiluminescence for NOx, UV fluorescence for SO₂, and non-dispersive infrared for CO.
• Cloud-Based Data Handling: Modern CAAQMS systems integrate with cloud platforms for real-time data analytics, dashboarding, and API-based public access.
• Calibration and Maintenance Protocols: CPCB mandates quarterly calibration and routine maintenance by certified vendors to ensure high-quality data integrity.

Challenges and Limitations

• High Installation and Maintenance Costs: One station may cost ₹1–1.5 crore, with additional annual maintenance and calibration expenses.
• Limited Rural Coverage: While urban areas are prioritized, rural and peri-urban areas remain under-monitored.
• Data Quality Issues: Sensor drift, power failures, and lack of skilled manpower occasionally affect data quality and continuity.
• Integration Gaps: Not all CAAQMS stations are seamlessly integrated with AI/ML-based forecasting systems or public information dashboards.

Recent Developments (2023–2024)

• CPCB is working on expanding the network to Tier-2 and Tier-3 cities.
• Use of low-cost sensors and satellite data is being explored to supplement fixed CAAQMS stations.
• Collaboration with startups and IoT providers is increasing under the Digital India framework.
• Data integration with AQMS Grids, Urban Local Body Dashboards, and State Pollution Control Boards is being standardized.

National Ambient Air Quality Standards (NAAQS)

Introduction
The National Ambient Air Quality Standards (NAAQS) are a set of air quality benchmarks that define the permissible concentration levels of various air pollutants in the ambient atmosphere. These standards are notified by the Central Pollution Control Board (CPCB) under the authority of the Air (Prevention and Control of Pollution) Act, 1981, and framed under the broader provisions of the Environment (Protection) Act, 1986.

The purpose of NAAQS is to safeguard public health, ecosystems, and climate by establishing scientifically determined pollutant concentration limits that should not be exceeded in any part of the country. These standards guide regulatory interventions, pollution control strategies, environmental impact assessments, and public health advisories.

Nodal Ministry and Authority

• Nodal Ministry: Ministry of Environment, Forest and Climate Change (MoEF&CC)
• Regulatory Body: Central Pollution Control Board (CPCB)
• Legal Framework: Air (Prevention and Control of Pollution) Act, 1981; Environment (Protection) Act, 1986
• First Notified: 1982
• Revised and Expanded: In November 2009, CPCB notified revised and comprehensive NAAQS applicable uniformly to both rural and urban areas

Key Objectives of NAAQS

• To define safe limits for various air pollutants affecting health, vegetation, buildings, and climate
• To establish a scientific basis for assessing air quality
• To provide a benchmark for issuing health advisories, environmental clearances, and compliance checks
• To guide the creation of Air Quality Index (AQI), zoning regulations, and emission norms
• To enable formulation and enforcement of pollution control measures across sectors

Pollutants Covered under NAAQS (2009 Revision)

The 2009 notification specifies standards for 12 key pollutants, with detailed permissible limits over short-term (24 hours, 8 hours) and long-term (annual) exposure periods:

Pollutant	Time-Weighted Average	Concentration Limit (µg/m³)
Particulate Matter (PM₁₀)	24-hour	100
	Annual	60
Particulate Matter (PM₂.₅)	24-hour	60
	Annual	40
Sulphur Dioxide (SO₂)	24-hour	80
	Annual	50
Nitrogen Dioxide (NO₂)	24-hour	80
	Annual	40
Carbon Monoxide (CO)	8-hour	2.0 mg/m³
	1-hour	4.0 mg/m³
Ozone (O₃)	8-hour	100
	1-hour	180
Lead (Pb)	24-hour	1.0
	Annual	0.5
Ammonia (NH₃)	24-hour	400
Benzene (C₆H₆)	Annual	5
Benzo(a)pyrene [BaP]	Annual	1
Arsenic (As)	Annual	6
Nickel (Ni)	Annual	20

Note: These limits are applicable uniformly to industrial, residential, rural, and ecologically sensitive areas across the country.

Salient Features of NAAQS (2009 Revision)

• For the first time, pollutants like PM2.5, Ozone, Ammonia, and Heavy Metals (Ni, As, BaP) were included
• The standards apply equally to rural and urban areas, recognizing growing pollution in smaller towns and peri-urban zones
• Multiple averaging periods (hourly, daily, and annual) help assess both acute and chronic exposure effects
• They form the scientific basis for:
  • Air Quality Index (AQI) categorization
  • City Action Plans under NCAP
  • Environmental Impact Assessment (EIA) criteria for projects

Legal Status and Enforcement

• Although NAAQS are non-justiciable, they are binding benchmarks used by environmental authorities for:
  • Issuing show cause notices
  • Imposing closure directions
  • Framing zoning regulations and emission limits
• Compliance is monitored under programmes like:
  • National Air Quality Monitoring Programme (NAMP)
  • Continuous Ambient Air Quality Monitoring System (CAAQMS)
  • Air Quality Index (AQI) portal developed by CPCB and SAFAR (IITM)

Role in NCAP (National Clean Air Programme)

Under the National Clean Air Programme (NCAP), the ultimate target is to reduce PM10 and PM2.5 levels and bring all non-attainment cities within the NAAQS limits by 2025–26. City-level interventions, funding, and performance evaluations are all based on how close the cities come to achieving NAAQS-defined limits.

Challenges in NAAQS Implementation

• Non-compliance in urban areas due to vehicular congestion, industrial emissions, and construction dust
• Data gaps in smaller cities where monitoring stations are absent or poorly maintained
• Lack of enforcement mechanisms in rapidly growing towns
• Limited public awareness of the thresholds and their health implications

Air (Prevention and Control of Pollution) Act, 1981

Introduction
The Air (Prevention and Control of Pollution) Act, 1981, is a parliamentary legislation enacted to provide a comprehensive legal framework for the prevention, control, and abatement of air pollution in India. It was passed by the Parliament of India in March 1981 and came into force on 16th May 1981. The Act was legislated under Article 253 of the Constitution of India, enabling the Parliament to enact laws to implement international agreements—in this case, the 1972 Stockholm Conference on Human Environment.

The Act is a key environmental law that empowers both Central and State Pollution Control Boards to monitor air quality, regulate emissions, and take legal action against violators. It complements other major environmental laws such as the Water (Prevention and Control of Pollution) Act, 1974, and the Environment (Protection) Act, 1986.

Nodal Ministry and Regulatory Authorities

• Nodal Ministry: Ministry of Environment, Forest and Climate Change (MoEF&CC)
• Central Regulatory Authority: Central Pollution Control Board (CPCB)
• State Regulatory Authorities: State Pollution Control Boards (SPCBs) or Pollution Control Committees (PCCs) in Union Territories

Objectives of the Act

• To prevent, control, and abate air pollution in India
• To ensure the preservation of air quality
• To establish a central and state-level institutional mechanism for air quality monitoring and enforcement
• To regulate the establishment and operation of industrial plants and vehicles contributing to air pollution
• To empower boards to take corrective and punitive actions against violators

Key Definitions Under the Act

• Air Pollutant: Any solid, liquid, or gaseous substance (including noise) present in the atmosphere in concentrations that may be harmful to human beings, other living creatures, plants, property, or the environment.
• Emission: Any solid, liquid, or gaseous substance coming out from any chimney, duct, or flue or any other outlet.
• Approved Appliances: Equipment approved by the Board which conforms to the prescribed emission standards.

Salient Features and Provisions

Establishment of Pollution Control Boards

• The Central Pollution Control Board (CPCB) is responsible for planning and executing nationwide programmes.
• Each state must establish a State Pollution Control Board (SPCB) to carry out functions under the Act at the regional level.

Power to Set Air Quality Standards

• The CPCB is authorized to prescribe National Ambient Air Quality Standards (NAAQS).
• SPCBs may set more stringent standards in specific areas, considering the ecological and demographic characteristics.

Control of Industrial Emissions

• No person shall, without prior consent of the State Board, establish or operate any industrial plant in an air pollution control area.
• Consent includes specifications regarding the treatment and control equipment to be used.
• SPCBs can deny or withdraw consent and order closure of units violating emission norms.

Declaration of Air Pollution Control Areas

• The State Government, after consultation with the SPCB, may declare any area or part of an area as an air pollution control area by notification in the Official Gazette.
• In such areas, stricter regulations on fuel use, industrial activity, and vehicular emissions are enforced.

Sampling and Inspection Powers

• Pollution Control Boards have the power to:
  • Inspect industrial units
  • Take samples of emissions
  • Examine air pollution control equipment
  • Direct the installation of emission control devices

Legal Enforcement and Penalties

• Failure to comply with the provisions can result in:
  • Imprisonment up to 3 months
  • Fines up to ₹10,000
  • Additional fines for continued non-compliance (₹5,000 per day)

Appeal Mechanism

• Any person aggrieved by an order of the State Board may appeal to an Appellate Authority constituted by the State Government.

Amendments and Developments

• While the Air Act has not been significantly amended since 1987, various rules and notifications have been issued under the Act to address contemporary challenges such as:
  • Vehicular emission norms (Bharat Stage standards)
  • Ban on burning of agricultural waste in certain states
  • Pollution control guidelines for construction and demolition activities

Limitations of the Act

• Reactive rather than preventive in some aspects, with limited provisions for proactive pollution prevention
• Weak enforcement mechanisms in several states due to lack of manpower, monitoring infrastructure, and technical capacity
• Penalties are outdated and inadequate, lacking deterrent value in major pollution cases
• The Act does not cover indoor air pollution or transboundary pollution clearly

Environment (Protection) Act, 1986

Introduction
The Environment (Protection) Act, 1986 is a comprehensive legislation enacted by the Parliament of India to provide a framework for the protection and improvement of the environment. It was passed in March 1986 and came into force on 19th November 1986, in the wake of the Bhopal Gas Tragedy (1984)—one of the world’s worst industrial disasters.

This Act serves as an umbrella legislation that authorizes the central government to take all necessary measures to prevent, control, and abate environmental pollution, and to safeguard the environment. It enables the government to coordinate with various environmental authorities, enforce rules, and regulate activities that pose threats to air, water, soil, and biodiversity.

Nodal Ministry and Legal Authority

• Nodal Ministry: Ministry of Environment, Forest and Climate Change (MoEF&CC)
• Date of Enactment: March 1986
• Date of Enforcement: 19th November 1986
• Enacted Under: Article 253 of the Constitution (to implement international conventions)
• Legal Basis: Powers derived from India’s participation in the 1972 United Nations Conference on the Human Environment (Stockholm Conference)

Objectives of the Act

• To provide for the protection and improvement of the environment
• To empower the Central Government to take measures to address environmental hazards
• To coordinate activities of various regulating agencies established under other environment-related laws
• To enact rules and standards for the control of emissions and discharges of pollutants
• To ensure the punishment of violators through stringent penalties

Key Definitions under the Act

• Environment: Includes water, air, land, and the interrelationship among them and with human beings, animals, plants, microorganisms, and property
• Environmental Pollutant: Any solid, liquid or gaseous substance present in such concentration as may be or tend to be injurious to environment
• Environmental Pollution: The presence of any environmental pollutant in the environment
• Hazardous Substance: Any substance or preparation which, due to its chemical or physico-chemical properties or handling, is liable to cause harm

Salient Features of the Act

• Wide Powers to Central Government:
  The Act gives broad powers to the Central Government to:
  • Take measures to protect and improve environmental quality
  • Coordinate actions of states and other authorities
  • Plan and execute national programmes
  • Set standards for emissions and effluents
  • Restrict areas for industrial operation
  • Lay down procedures for handling hazardous substances
• Delegated Legislation:
  Allows the government to make rules, notifications, and guidelines on a wide range of environmental issues without going back to Parliament
• Superseding Authority:
  The Act overrides the provisions of other laws in case of inconsistency, thereby giving it overriding authority over all environment-related matters

Major Rules and Notifications Issued Under This Act

Several crucial rules and regulations derive authority from the Environment (Protection) Act:

• Environment (Protection) Rules, 1986
  • General standards for the discharge of pollutants
  • Industry-specific emission norms
  • Prescribed limits for air, water, and noise pollution
• Hazardous Waste Management Rules (1989, revised 2016)
  • Safe handling, storage, and disposal of hazardous waste
• Bio-Medical Waste Management Rules, 2016
  • Management and disposal of biomedical waste from hospitals and labs
• Plastic Waste Management Rules, 2016 (amended in 2022)
  • Ban on single-use plastics
  • Extended Producer Responsibility (EPR)
• E-Waste Management Rules, 2016
  • Collection, recycling, and disposal of electronic waste
• Solid Waste Management Rules, 2016
  • Segregation, processing, and disposal of municipal solid waste
• Noise Pollution (Regulation and Control) Rules, 2000
  • Ambient noise standards for different zones
• Environmental Impact Assessment (EIA) Notification, 2006
  • Mandatory assessment for industrial, infrastructure, and mining projects
• Coastal Regulation Zone (CRZ) Notification, 2011 (revised 2019)
  • Controls on construction and development in ecologically sensitive coastal areas

Enforcement and Penalties

• Penalty for Non-Compliance:
  Any person who fails to comply with the Act or its rules can face:
  • Imprisonment up to 5 years
  • Fine up to ₹1 lakh
  • Additional fine of ₹5,000 per day for continued violation
  • Imprisonment may extend up to 7 years if failure continues beyond one year
• Power to Issue Directives:
  The Central Government can issue written directions to:
  • Close, prohibit, or regulate any industry or operation
  • Stop or regulate the supply of electricity, water, or other services

Importance of the Act

• Acts as the mother legislation for environmental regulation in India
• Provides a unified framework for controlling air, water, noise, and land pollution
• Facilitates India’s compliance with international environmental agreements
• Authorizes and enables rapid response to environmental emergencies

Limitations and Challenges

• Centralized enforcement often leads to weak implementation at the local level
• Insufficient manpower and technical capacity in Pollution Control Boards
• Low public awareness about provisions and complaint mechanisms
• Limited inter-agency coordination among environmental, industrial, and urban departments
• Penalties need to be updated to match modern industrial economics and technology risks

Recent Reforms and Developments

• Draft Environment (Protection) Amendment Bill, 2022 proposed changes such as:
  • Decriminalization of minor violations
  • Introduction of environmental penalties instead of imprisonment in certain cases
  • Promotion of ease of doing green business
• Emphasis on Extended Producer Responsibility (EPR) across waste management rules
• Introduction of online compliance tracking systems and digital consent processes by CPCB

Bharat Stage (BS) Emission Norms

The Bharat Stage (BS) emission standards are regulatory norms set by the Government of India to control the output of air pollutants from internal combustion engine vehicles. These norms are broadly based on the European emission standards (Euro norms) and are enforced by the Central Pollution Control Board (CPCB) under the Ministry of Environment, Forest and Climate Change (MoEFCC).

Objective of Bharat Stage Norms

• To reduce air pollution caused by vehicles by regulating the amount of particulate matter (PM) and gaseous pollutants like:
  • Carbon monoxide (CO)
  • Nitrogen oxides (NOₓ)
  • Hydrocarbons (HC)
  • Sulfur dioxide (SO₂)
  • Particulate matter (PM2.5 and PM10)
• To align Indian emission control mechanisms with international practices, especially with the European Union.

Timeline and Evolution of BS Norms in India

Bharat Stage Norm	Year of Implementation	Key Highlights
BS-I	2000	Based on Euro I; introduced in Delhi first
BS-II	2001 (Delhi); 2005 (nationwide)	Based on Euro II; mandated use of low-sulfur fuel
BS-III	2005 (metros); 2010 (nationwide)	Based on Euro III; limited NOₓ and HC more strictly
BS-IV	2010 (metros); 2017 (nationwide)	Better control of PM and NOₓ; required improved fuel and engine tech
BS-VI	April 1, 2020 (Skipped BS-V)	Drastic reductions in PM, NOₓ, HC; mandatory OBD and DPF systems

Note: India skipped BS-V to leapfrog directly from BS-IV to BS-VI, reflecting the urgency to combat rising air pollution, especially in urban areas.

3. Key Differences Between BS-IV and BS-VI

Parameter	BS-IV	BS-VI
Sulfur in fuel	50 ppm	10 ppm (80% reduction)
Particulate Matter (Diesel)	Limited	80% reduction in PM emissions
NOₓ emission (Diesel)	Moderate	~70% reduction
On-board diagnostics (OBD)	Optional or basic	Mandatory for all vehicles
Real Driving Emission (RDE)	Not applicable	Introduced in phases starting 2023
OBD-II norms	Not mandatory	OBD-II mandatory from April 2023
Engine tech	Fuel injection allowed	Requires advanced tech like DPF, SCR, OBD

Technologies Introduced with BS-VI

To meet BS-VI norms, automobile manufacturers had to integrate the following systems:

a. Diesel Particulate Filter (DPF)

• Captures fine PM (PM2.5 and PM10) from diesel exhaust.

b. Selective Catalytic Reduction (SCR)

• Injects urea-based AdBlue fluid to convert NOₓ into N₂ and H₂O.

c. Exhaust Gas Recirculation (EGR)

• Recirculates part of exhaust to reduce combustion temperature and NOₓ.

d. On-Board Diagnostics (OBD)

• Monitors real-time emissions and system health.

Impact of BS Norms on Air Quality and Industry

Positive Outcomes

• Drastic reduction in sulfur and PM emissions, especially from diesel vehicles.
• Promotes adoption of cleaner fuel and electric vehicles.
• Push for refinery upgrades by Indian Oil, HPCL, and BPCL to produce BS-VI compliant fuel.

Challenges Faced

• Higher vehicle costs due to expensive emission-control systems.
• Fuel adulteration and availability in rural areas.
• Initial supply chain stress during BS-VI transition.

Regulatory Framework and Enforcement

• Enforced by CPCB under the Air (Prevention and Control of Pollution) Act, 1981.
• Supported by state transport departments, Pollution Under Control (PUC) Centers, and Automobile Research Association of India (ARAI).
• Manufacturers must obtain Type Approval Certificates for new vehicles under BS norms.

Way Forward: Post BS-VI Developments

India is preparing for:

• BS-VI Stage 2 (from April 2023): Includes Real Driving Emission (RDE) testing.
• Introduction of Electric Vehicles (EVs) and Hybrid systems as alternatives.
• Integration of fuel efficiency standards and carbon footprint monitoring.
• Government incentives under schemes like FAME-II for cleaner mobility.

Environment and Ecology Notes >>

Agroforestry

Terrestrial Ecosystem

Functions of an Ecosystem, Food Chain, Ecological Pyramids, Biogeochemical Cycles

Ecology-Environment, Ecosystem, Ecotone, Biome

Climate Change

Climate Change and Climate Action

Climate Change and India: Policies, Impacts, and

Paris Agreement: A Comprehensive Overview

Kyoto Protocol: A Comprehensive Overview

Pollution

Indian Megacities Lag in Air Pollution Control

Biodiversity

Forest Conservation & Augmentation Act, 2023

Mangrove Ecosystem: Importance, Conservation, and Challenges

Wetland Ecosystem, Ramsar Convention

Biological Diversity Act, 2002 & Biological Diversity

Convention on Biological Diversity (CBD)