Consider the following statements: Statement I: Studies indicate that carbon dioxide emissions from cement industry account for more than 5% of global carbon emissions. Statement II: Silica-bearing clay is mixed with limestone while manufacturing cement. Statement III: Limestone is converted into lime during clinker production for cement manufacturing. Which one of the following is correct in respect of the above statements?

1. A. Both Statement II and Statement III are correct and both of them explain Statement I
2. B. Both Statement II and Statement III are correct but only one of them explains Statement I
3. C. Only one of the Statements II and III is correct and that explains Statement I
4. D. Neither Statement II nor Statement III is correct

Answer: A

Explanation

Statement I is correct: The cement industry is a major contributor to global CO2 emissions, accounting for approximately 8% of anthropogenic CO2, which is indeed more than 5%. Statement II is correct: Silica-bearing clay is mixed with limestone as raw materials in cement manufacturing. This process, along with the energy required, contributes to CO2 emissions. Statement III is correct: During clinker production, limestone (calcium carbonate) undergoes calcination at high temperatures, converting it into lime (calcium oxide) and releasing a significant amount of CO2. Both the chemical process (calcination of limestone) and the energy-intensive heating of raw materials like silica-bearing clay contribute substantially to the cement industry’s high CO2 emissions, thus explaining Statement I. The environmental impact of industrial processes and strategies for decarbonization are crucial topics for UPSC.