MAINS PREVIOUS YEAR QUESTIONS (Unit 2 )
Q.1) Discuss in detail the photochemical smog emphasizing its formation, effects and mitigation. Explain the 1999 Gothenburg Protocol. (2022)
Introduction | Photochemical smog is a type of air pollution formed when sunlight interacts with nitrogen oxides (NOₓ) and volatile organic compounds (VOCs) in the atmosphere, producing harmful secondary pollutants like ozone (O₃) and peroxyacetyl nitrate (PAN). It is a prominent issue in urban areas with high vehicular traffic and industrial activities, affecting air quality, human health, and ecosystems. The 1999 Gothenburg Protocol is a key international treaty aimed at reducing such transboundary air pollution in Europe. |
Body | Formation of Photochemical Smog
Effects of Photochemical Smog
Mitigation Measures
The 1999 Gothenburg Protocol
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Conclusion | Photochemical smog remains a critical environmental challenge with severe implications for health, ecosystems, and climate. Addressing it requires integrated strategies including regulatory controls, cleaner technologies, sustainable urbanization, and international cooperation through frameworks like the Gothenburg Protocol. Collective action at local, national, and global levels is indispensable for ensuring cleaner air and healthier lives. |
Q.2) Describe the key points of the revised Global Air Quality Guidelines (AQGs) recently released by the World Health Organisation (WHO). How are these different from its last update in 2005? What changes in India’s National Clean Air Programme are required to achieve these revised standards?
Introduction | The World Health Organization (WHO) released its revised Global Air Quality Guidelines (AQGs) in September 2021, after 16 years since the 2005 update. These guidelines set more stringent limits on key air pollutants, based on newer evidence showing significant health risks even at lower concentrations. They aim to guide countries in framing effective policies for cleaner air. India’s National Clean Air Programme (NCAP) needs to be strengthened to move towards meeting these revised global benchmarks. | ||||||||||||||||||||||||
Body | Key Points of Revised WHO AQGs (2021) The 2021 guidelines were developed based on robust epidemiological and toxicological studies showing health impacts even below earlier thresholds. They set more stringent limits for six key pollutants:
o PM₂.₅ (annual mean): reduced from 10 µg/m³ → 5 µg/m³ o PM₁₀ (annual mean): reduced from 20 µg/m³ → 15 µg/m³
o Annual mean: reduced from 40 µg/m³ → 10 µg/m³
o Recommended limits for these pollutants were also tightened, considering latest evidence.
o Designed to help countries progress step by step from current levels towards the ideal AQGs.
o Emphasizes protecting children, elderly, and marginalized populations who face greater exposure risks.
o Recognizes environmental justice by highlighting unequal pollution burdens among communities. How 2021 Guidelines Differ from 2005
Changes Required in India’s NCAP
Reforms needed: Ambitious targets:
Legal enforceability & accountability:
Strengthen monitoring & reporting:
Sector-specific action:
Urban planning & infrastructure:
Public engagement:
Research & capacity building:
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Conclusion | The revised WHO AQGs reflect the urgency of addressing air pollution, given its severe health and environmental consequences even at low concentrations. India’s NCAP must evolve to meet these ambitious yet essential benchmarks, through stronger targets, better implementation, and inclusive, multi-sectoral strategies. Aligning with these standards is crucial for ensuring the right to clean air and safeguarding public health. |
Q.3) Industrial pollution of river water is a significant environmental issue in India. Discuss the various mitigation measures to deal with this problem and also the government’s initiatives in this regard. (2024)
Introduction | Industrial pollution is a major contributor to the degradation of river ecosystems in India. Untreated or inadequately treated effluents containing toxic chemicals, heavy metals, and organic pollutants from industries contaminate rivers, harming aquatic life, agriculture, and human health. Prominent examples include pollution in the Ganga, Yamuna, and Sabarmati rivers. Addressing industrial river pollution is crucial for environmental sustainability, public health, and economic well-being. |
Body | Mitigation Measures Effective management of industrial pollution of river water requires technological, regulatory, and participatory interventions: A. Technological Interventions Effluent Treatment Plants (ETPs): · Mandatory for industries to install and operate ETPs for treating wastewater before discharge. · Regular monitoring and upgrading of ETP technology to meet prescribed standards. Common Effluent Treatment Plants (CETPs): · Developed for clusters of small and medium-scale industries where individual ETPs are economically unviable. · Promotes cost-effective and collective treatment of wastewater. Cleaner Production Techniques: · Adoption of zero liquid discharge (ZLD) technologies. · Use of environmentally friendly raw materials and closed-loop water use systems. Water Recycling and Reuse: · Encouraging industries to recycle treated water for internal processes to minimize freshwater withdrawal and effluent discharge. B. Regulatory and Policy Measures Stricter Enforcement of Standards: · CPCB and SPCBs enforce discharge standards under the Water (Prevention and Control of Pollution) Act, 1974. · Periodic inspections, fines, and closure of defaulting industries. Polluter Pays Principle: · Industries made liable to pay for damage caused by pollution and cost of restoration. Zoning Regulations: · Establishing designated industrial zones away from ecologically sensitive river stretches. Public Participation: · Citizen monitoring and reporting of pollution through grievance redressal portals. Government Initiatives Several national-level programs and schemes aim to address river pollution from industrial sources: A. National Missions
o Comprehensive river conservation program focusing on Ganga and its tributaries. o Emphasis on ETPs, CETPs, real-time monitoring, and industrial compliance.
o Dedicated authority under the Environment Ministry for Ganga basin management.
o Addresses pollution in major rivers like Yamuna, Godavari, Krishna, and others by funding sewage and industrial effluent management projects. B. Regulatory Framework
C. Monitoring Mechanisms
D. Financing and Incentives
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Conclusion | Industrial pollution of rivers poses a serious threat to India’s water security, biodiversity, and public health. Effective mitigation requires a holistic approach involving strict enforcement of laws, technological upgradation, cleaner production, and active participation of all stakeholders. Strengthening initiatives like Namami Gange and extending similar efforts to other polluted rivers, alongside enhancing monitoring and accountability, are essential to ensure sustainable and clean river systems for future generations. |
Q.4) What is a wetland? Explain the Ramsar concept of ‘wise use’ in the context of wetland conservation. Cite two examples of Ramsar sites from India. (2018)
Introduction | A wetland is a transitional ecosystem between terrestrial and aquatic habitats, where the water table is at or near the surface or the land is covered by shallow water. According to the Ramsar Convention (1971), wetlands include marshes, swamps, peatlands, estuaries, mangroves, lagoons, lakes, and even some human-made water bodies, whether natural or artificial, permanent or temporary, with water that is static or flowing, fresh, brackish or saline. |
Body | Ramsar Concept of ‘Wise Use’
Key features of wise use:
Examples of Ramsar Sites from India India is a signatory to the Ramsar Convention and, as of now, has 75 Ramsar sites. Two notable examples:
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Conclusion | Wetlands are vital ecosystems providing numerous ecological, economic, and cultural services. The Ramsar concept of wise use underlines the importance of sustainable management of wetlands, ensuring that conservation and development go hand in hand. Strengthening community involvement, enforcing regulations, and integrating wetland management into national planning are essential for achieving this vision. |