From 692 Kilometers to Barely 1,048 Hills: Redefining the Aravallis
On November 27, 2025, the Supreme Court formally accepted the Union Environment Ministry’s recommendation to reclassify the definition of the Aravalli Hills. This new definition uses a 100-metre height threshold to determine the extent of the range, leaving a staggering 90% of the historical Aravallis excluded. By this metric, no more than 1,048 hills—only 8.7% of the original range—remain protected, severely narrowing the geographical scope of ecological safeguards. The implications for sustainable development, mining regulation, and environmental resilience in India’s most fragile landscapes are extraordinary.
The Aravallis: From Natural Barrier to Bureaucratic Afterthought
This decision by the apex court marks a decisive shift in how the Aravallis are treated under Indian environmental law and policy. Historically recognized as the oldest mountain range in India, stretching over 692 kilometres across Rajasthan, Haryana, Gujarat, and culminating in Delhi, the Aravallis have played an irreplaceable role in ecological stability. They constitute a vital natural barrier against the spread of the Thar Desert, regulate monsoon rainfall, and protect the National Capital Region (NCR) from worsening air pollution.
Yet, the new technical definition strips away much of this natural significance. By raising the height threshold to 100 metres and excluding “adjacent landforms,” the Ministry has significantly shrunk the protective scope of the range, exposing vast tracts to potential mining and urban sprawl. For decades, the Forest Survey of India (FSI) relied on a more inclusive criterion: a landform with a 3-degree slope since 2010, or a modified 4.57-degree slope with a 30m height cutoff proposed in 2024. Both would have covered at least 40% of the Aravallis. The current definition radically departs from these precedents.
The Invisible Machinery Behind the Decision
The Supreme Court’s endorsement of the Ministry’s recommendations arose from a technical committee convened in 2024 to end long-standing legal ambiguities. Legislative ambiguities in the Environment Protection Act, 1986 have enabled different definitions of "hills" across states, often leaving room for illegal mining operations to maneuver through legal loopholes. The judiciary sought a harmonized definition in response to extensive environmental litigation—prompted in part by disappearing ridgelines in states such as Rajasthan, where mining accounts for over 17% of state GDP.
While the intention to standardize definitions was commendable, the chosen benchmark leaves glaring gaps. By implying that any structure below 100m elevation is not an “Aravalli,” swathes of hills in southern Rajasthan and Haryana, which function as wind and moisture regulators, are stripped of legal status. Furthermore, the Ministry’s list of affected zones conspicuously omits districts like Bhilwara and Nagaur, where rampant illegal mining continues despite consistent environmental audits. This dilution of criteria raises questions about selective prioritization.
Claims vs. Reality: What Is Being Protected?
Despite framing the updated definition as an instrument of sustainable development, its practical effects contradict these stated objectives:
- 90% exclusion: Under the new definition, Aravallis now cover only 8.7% of their historical area, per FSI data.
- Functionality compromised: Research on the range’s role as a wind barrier highlights the importance of even 20-metre ridges for protecting NCR’s air quality. Limiting protection to hills above 100m disregards such functionality entirely.
- Legal gaps persist: Districts with a visible presence of Aravalli formations are conspicuously absent in the Ministry’s formal district list, enabling unchecked construction and mining.
While the Court has asked the Ministry to develop a Management Plan for Sustainable Mining, the institutional mechanism—overseen by the Indian Council of Forestry Research and Education (ICFRE)—has no track record of addressing resource conflicts on such a scale. Without clarity on enforcement or on-ground audits, the gap between intent and execution risks becoming insurmountable.
The Wider Environmental Risk
The fallout from this narrow definition cannot be viewed in isolation. With the Aravallis losing protection, NCR’s already precarious air, water, and soil quality are likely to worsen. Rajasthan contributes 40% of the national output in sandstone production; much of this takes place within the Aravalli belt, fueling both legal and illegal mining. Lax oversight could exacerbate the exploitation of these resources, threatening critical groundwater recharge zones and aggravating desertification along the western frontier.
This decision, ironically, contradicts the global shift toward expanded ecological conservation in threatened ecosystems. Take Kenya, for instance. After devastating drought cycles affected the Mau Forest Complex, pivotal to East Africa’s water cycles, Kenya expanded the forest boundaries in 2018 to include buffer zones and auxiliary ridges under the same conservation framework. Contrastingly, India is narrowing the protective scope of a similarly fragile ecosystem, undermining its long-term ecological stability.
Uncomfortable Questions for the State and Judiciary
The Supreme Court’s imprimatur on the redefinition raises valid concerns over whether environmental concerns have ceded ground to developmental imperatives:
First, why did the Court approve a 100m benchmark when scientific evidence indicates that even 20m-high ridgelines can prevent desert winds and mitigate air pollution? Second, shouldn’t the Ministry have commissioned field-based ecological studies—rather than merely relying on FSI topographical surveys—before calibrating protection measures?
Additionally, attention must now turn to the proposed Management Plan for Sustainable Mining. Will the focus of conservation shift entirely from preventing illegal mining to enabling “sustainable” legal mining? It remains to be seen whether the ICFRE can operationalize such a plan equitably when state-level dynamics differ significantly. For instance, Gujarat has succeeded in enforcing mining bans through state-specific biodiversity conservation laws, whereas enforcement in Rajasthan and Haryana remains abysmal due to lack of political will.
Lastly, the timing raises eyebrows. With general elections around the corner in 2026, the inclusion of mining reform in the political narrative seems less coincidental. Mining lobbies, especially in Rajasthan and Haryana, are hard to ignore in electoral calculus.
A Stark Moment of Reckoning
The Aravallis are at a historical inflection point. The Court’s acquiescence to the Ministry’s narrow framework echoes a troubling trend of prioritizing economic expediency over ecological necessity—similar to earlier dilutions of the Coastal Regulation Zone (CRZ) Notifications. Much now depends on how rigorously the central and state governments enforce what remains of legal protection, though examples from neighboring states offer little optimism.
- Which criterion is used in the new definition of the Aravalli Hills under the Supreme Court-endorsed framework?
(a) Landforms with a 20-metre height and adjacent slope
(b) Landforms with a 4.57-degree slope and a 30-metre height cutoff
(c) Landforms of 100-metre height above local relief
(d) All landforms part of the FSI Aravalli Range
Answer: (c) - Which Indian state accounts for the largest geographical share of the Aravalli Range?
(a) Haryana
(b) Rajasthan
(c) Gujarat
(d) Delhi
Answer: (b)
Practice Questions for UPSC
Prelims Practice Questions
- A higher minimum-height cutoff can reduce the legally protected footprint even if lower ridges perform important ecological functions.
- A slope-based criterion can potentially include more landforms than a strict height-only criterion, depending on the thresholds used.
- Excluding “adjacent landforms” can narrow the regulatory scope for controlling mining and urban expansion in connected landscapes.
Which of the above statements is/are correct?
- Legal ambiguity in defining “hills” can create opportunities for illegal mining to exploit loopholes across states.
- A harmonised definition necessarily strengthens ecological protection because it removes interpretational differences.
- If districts with visible hill formations are omitted from official lists, construction and mining controls may weaken in those areas.
Which of the above statements is/are correct?
Frequently Asked Questions
Why is the Supreme Court’s acceptance of a 100-metre threshold significant for Aravalli governance?
Accepting a 100-metre height threshold operationally narrows what legally counts as “Aravalli Hills,” shrinking the space where environmental safeguards can apply. This reclassification can alter how regulators treat mining, construction, and land-use change in areas earlier considered part of the Aravalli landscape.
How does the new definition differ from earlier approaches used to identify Aravalli hill formations?
Earlier approaches referenced by the Forest Survey of India used slope-based criteria (a 3-degree slope since 2010) and a proposed 2024 modification (4.57-degree slope with a 30m height cutoff), both of which would have covered at least 40% of the range. The new approach excludes “adjacent landforms” and uses a higher 100m benchmark, resulting in far less coverage.
What institutional and legal factors contributed to the push for a harmonised definition of “hills”?
Ambiguities in the Environment Protection Act, 1986 enabled multiple state-level interpretations of “hills,” creating room for illegal mining to exploit definitional loopholes. A technical committee formed in 2024 sought to reduce such ambiguity, and the Court’s endorsement followed this committee-driven standardisation effort.
Why can a height-only definition be ecologically problematic in the Aravalli context?
The article notes that even 20-metre ridges can function as wind barriers that help protect NCR’s air quality, implying that ecological function does not map neatly to a 100m cutoff. By treating sub-100m features as outside the Aravallis, functionally important landforms may lose legal recognition and protection.
What enforcement and implementation concerns arise from the proposed ‘Management Plan for Sustainable Mining’?
Although the Court asked the Ministry to develop a Management Plan for Sustainable Mining, the institutional mechanism overseen by ICFRE is described as lacking a track record in managing resource conflicts of this scale. The article highlights uncertainty on enforcement and on-ground audits, which can widen the gap between policy intent and outcomes.
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