UPSC CSE Prelims
Environment & Ecology Previous Year Questions (PYQs)

Detailed Explanation:

Answer: Option 4 — 1, 2 and 3

All three statements about coal combustion and Indian coal characteristics are correct. Coal ash contains heavy metals, coal-fired power plants release sulfur and nitrogen oxides, and Indian coal is characterized by high ash content.

✅ Statement 1 – Correct: Coal ash, a by-product of coal combustion, contains toxic heavy metals including arsenic, lead, and mercury, which can leach into water bodies and contaminate soil, posing environmental and health hazards.

✅ Statement 2 – Correct: Coal-fired power plants release sulfur dioxide (SO₂) and nitrogen oxides (NOₓ) during combustion, which contribute to acid rain, respiratory issues, smog formation, and overall air pollution.

✅ Statement 3 – Correct: Indian coal, especially from eastern and central regions, has high ash content (30-50%), which reduces its calorific value, increases pollution levels, and results in large quantities of fly ash generation in thermal power plants.

📝 Short Notes: Coal Combustion and Environmental Impact

• Coal Ash Composition: Contains heavy metals (arsenic, lead, mercury, chromium, cadmium) that are toxic and carcinogenic; improper disposal can contaminate groundwater and soil.
• Air Pollutants from Coal Plants: Release SO₂ (causes acid rain), NOₓ (forms ground-level ozone and smog), particulate matter (PM2.5, PM10), CO₂ (greenhouse gas), and mercury emissions.
• Indian Coal Characteristics: High ash content (30-50% compared to 10-15% in imported coal), low calorific value (3000-4000 kcal/kg), and high moisture content.
• Fly Ash Utilization: India generates over 200 million tonnes of fly ash annually; used in cement manufacturing, brick making, road construction, and land filling.
• Environmental Regulations: MoEFCC mandates 100% fly ash utilization; thermal power plants must maintain electrostatic precipitators and FGD (Flue Gas Desulfurization) systems.

Detailed Explanation:

Answer: Option 3 — Nagarjunsagar-Srisailam

Nagarjunsagar-Srisailam Tiger Reserve, spread across five districts in Andhra Pradesh and Telangana, has the largest Critical Tiger Habitat (CTH) among the given options with a total area of approximately 3,728 sq. km. Critical Tiger Habitats are core areas of tiger reserves notified under the Wildlife Protection Act, 1972, which are kept inviolate for tiger conservation based on scientific evidence.

📝 Short Notes: Major Tiger Reserves and Their Critical Tiger Habitat Areas

• Critical Tiger Habitat (CTH): Also called core areas, these are inviolate zones notified under Section 38V of the Wildlife Protection Act, 1972, where human activities are prohibited or severely restricted.
• Buffer Zones: Areas surrounding CTH where limited human activity is permitted with conservation-oriented management.
• India has 53 tiger reserves (as of 2023) covering about 75,000 sq. km across 18 states.
• Project Tiger was launched in 1973 with 9 tiger reserves; Corbett was the first.

Detailed Explanation:

Answer: Option 1 — pesticides in agriculture

Carbofuran, methyl parathion, phorate, and triazophos are highly toxic organophosphate and carbamate pesticides used in agriculture. These chemicals are viewed with apprehension due to their severe toxicity to humans, non-target organisms, and the environment, leading to recommendations for their ban or phase-out by the Anupam Verma Committee in India.

📝 Short Notes: Hazardous Pesticides in India

• Organophosphates and Carbamates: These are two major classes of chemical pesticides that inhibit acetylcholinesterase enzyme, causing neurotoxic effects in pests and potentially in humans.
• Carbofuran: A carbamate insecticide banned in many countries; highly toxic to birds, fish, and mammals; used for soil and foliar treatment.
• Methyl Parathion: An organophosphate insecticide with extreme acute toxicity; banned or restricted globally due to human poisoning cases.
• Phorate: A systemic organophosphate insecticide; extremely hazardous with high dermal and oral toxicity.
• Triazophos: An organophosphate insecticide; moderately to highly toxic with environmental persistence concerns.
• Anupam Verma Committee (2013): Reviewed 66 pesticides banned abroad but used in India; recommended banning 13 and restricting others, leading to regulatory action by the Ministry of Agriculture.
• Government Action: Progressive banning and phase-out of hazardous pesticides to promote safer agricultural practices and protect public health and environment.

Detailed Explanation:

Answer: Option 3 — 3 only

Only Statement 3 is correct. The Ramsar Convention does not mandate protection of all wetlands in a country's territory, only those designated as Ramsar sites. The 2010 Rules were framed under the Environment (Protection) Act, 1986, not based on Ramsar recommendations. However, the 2010 Rules do include drainage areas and catchment regions in the definition of wetlands.

❌ Statement 1 – Incorrect: The Ramsar Convention requires contracting parties to designate suitable wetlands for international importance and promote their wise use, but does not mandate protection of all wetlands in the entire territory.

❌ Statement 2 – Incorrect: The Wetlands (Conservation and Management) Rules, 2010 were framed under the Environment (Protection) Act, 1986, not based on specific recommendations of the Ramsar Convention.

✅ Statement 3 – Correct: The 2010 Rules explicitly include the drainage area or catchment regions of wetlands as determined by the authority in the definition of 'wetland'.

📝 Short Notes: Wetlands Conservation Framework in India

• Ramsar Convention (1971): International treaty for conservation and wise use of wetlands; India is a signatory since 1982.
• Ramsar Sites in India: Countries designate specific wetlands of international importance; not all wetlands are covered.
• Wetlands (Conservation and Management) Rules, 2010: Framed under Environment (Protection) Act, 1986; included catchment areas in wetland definition.
• Wetlands (Conservation and Management) Rules, 2017: Replaced 2010 Rules; streamlined regulatory process and strengthened wetland conservation.
• Definition of Wetland: Includes areas of marsh, fen, peatland or water (natural or artificial, permanent or temporary) with water that is static or flowing, fresh, brackish or salt, including areas of marine water.
• Wise Use Concept: Maintenance of ecological character of wetlands through sustainable use compatible with conservation goals.

Detailed Explanation:

Answer: Option 3 — 1 and 3 only

This question tests knowledge of wildlife species and their natural habitats in India. Out of the three pairs given, only pairs 1 and 3 are correctly matched, while pair 2 incorrectly associates the Irrawaddy Dolphin with the Chambal River.

✅ Pair 1 – Correct: Blue-finned Mahseer is indeed naturally found in the Cauvery River and other rivers of the Deccan Plateau. It is an endangered freshwater fish species.

❌ Pair 2 – Incorrect: Irrawaddy Dolphin is NOT found in the Chambal River. The Chambal River is known for the Gangetic Dolphin. Irrawaddy Dolphins are found in coastal areas of South and Southeast Asia, and in India, they are found in Lake Chilika (Odisha).

✅ Pair 3 – Correct: Rusty-spotted Cat is naturally found in the Eastern Ghats. This small wild cat species is also found in the Western Ghats, central India, and Sri Lanka.

📝 Short Notes: Indian Wildlife Species and Habitats

Detailed Explanation:

Answer: Option 4 — Valley of Flowers National Park

Valley of Flowers National Park in Uttarakhand is situated entirely at a high altitude (3,352 to 3,658 metres above sea level) and lies completely within the temperate alpine zone. This zone is characterized by alpine meadows, low-growing vegetation, and a cooler climate suitable for high-altitude flowering plants.

Why other options are incorrect:
• Manas National Park (Assam): Located in tropical and subtropical zones with grasslands and evergreen forests, not alpine.
• Namdapha National Park (Arunachal Pradesh): Features diverse vegetation zones from tropical evergreen forests at lower elevations to sub-alpine meadows at higher altitudes, covering multiple zones.
• Neora Valley National Park (West Bengal): Extends from subtropical broadleaf forests at lower levels to temperate forests at higher reaches, not entirely alpine.

📝 Short Notes: Temperate Alpine Zone & National Parks

• Temperate Alpine Zone: High-altitude region above the tree line (typically above 3,000m in the Himalayas), characterized by alpine meadows, low shrubs, herbs, and grasses adapted to cold temperatures and short growing seasons.
• Valley of Flowers National Park: Located in Chamoli district, Uttarakhand; a UNESCO World Heritage Site known for endemic Himalayan flora with over 600 species of flowering plants; entirely within the alpine zone.
• Alpine Vegetation Characteristics: Cushion plants, dwarf shrubs, perennial herbs, and colorful wildflowers that bloom during the brief summer season; adapted to extreme cold, high UV radiation, and strong winds.
• Other Alpine Parks in India: Great Himalayan National Park (parts), Pin Valley National Park, and Hemis National Park also have alpine zones, but may not lie entirely within this zone.
• Altitude Zones in Himalayas: Tropical (up to 1,000m) → Sub-tropical (1,000-2,000m) → Temperate (2,000-3,000m) → Alpine (3,000-4,500m) → Glacial (above 4,500m).

Detailed Explanation:

Answer: Option 4 — textile fibre

The Himalayan nettle (Girardinia diversifolia) is a wild plant native to the Himalayan region that produces some of the longest natural fibres in the plant world, extracted from its stem. These fibres are strong, durable, and biodegradable, making them an excellent sustainable alternative to synthetic textiles and even comparable to flax or hemp fibres. The plant has gained attention in recent years as a source of eco-friendly textile material for the fashion and fabric industry.

📝 Short Notes: Himalayan Nettle (Girardinia diversifolia)

• Habitat: Found in the Himalayan regions of India, Nepal, Bhutan, and parts of China at altitudes of 1200-3000 meters.
• Fibre Characteristics: Produces fibres up to 2.5 meters long, which are among the longest natural plant fibres; they are strong, glossy, and have good moisture absorption properties.
• Textile Applications: Used for making eco-friendly fabrics, ropes, and traditional garments; can be blended with other natural fibres like cotton or wool.
• Sustainability: Requires minimal water, no pesticides, and grows wild; harvesting is done manually without harming the plant's root system, allowing regrowth.
• Economic Potential: Provides livelihood opportunities for Himalayan communities; being promoted as a sustainable alternative to synthetic fibres and cotton.

Detailed Explanation:

Answer: Option 4 — 1, 2 and 3

All three statements are correct as agricultural soils, cattle, and poultry industry are significant sources of reactive nitrogen compounds that contribute to environmental pollution and climate change.

✅ Statement 1 – Correct: Agricultural soils release nitrogen oxides (particularly nitrous oxide - N₂O) through microbial processes like nitrification and denitrification, especially from nitrogen-based fertilizers.

✅ Statement 2 – Correct: Cattle release ammonia (NH₃) into the environment primarily through urine and manure decomposition, contributing to air pollution and acid rain.

✅ Statement 3 – Correct: The poultry industry releases reactive nitrogen compounds including ammonia, nitrous oxide, and nitrogen oxides from manure management and feed production processes.

📝 Short Notes: Reactive Nitrogen Pollution

• Nitrogen Oxides (NOx): Primarily N₂O from agricultural soils; potent greenhouse gas with ~300 times the warming potential of CO₂; also contributes to ozone depletion.
• Ammonia (NH₃): Released from livestock waste and manure; forms particulate matter (PM2.5) in atmosphere; contributes to eutrophication when deposited in water bodies.
• Sources of Agricultural Nitrogen: Synthetic fertilizer application, animal manure, crop residue decomposition, and legume cultivation.
• Environmental Impacts: Air quality degradation, soil acidification, water pollution, biodiversity loss, and greenhouse gas emissions.
• Livestock Contribution: Global livestock sector responsible for ~10-12% of anthropogenic greenhouse gas emissions, with significant nitrogen compounds release.

Detailed Explanation:

Answer: Option 4 — Waste-to-energy technologies

Pyrolysis and plasma gasification are advanced thermochemical waste-to-energy technologies that convert waste materials into useful energy products. Pyrolysis involves heating organic waste in an oxygen-deficient environment to produce syngas, bio-oil, and char, while plasma gasification uses extremely high temperatures (created by plasma torches) to break down waste into syngas rich in hydrogen and carbon monoxide. Both processes offer sustainable solutions for waste management while generating energy, making them key technologies in the circular economy framework.

📝 Short Notes: Waste-to-Energy Technologies

• Pyrolysis: Thermal decomposition of organic materials at 300-900°C in the absence of oxygen, producing syngas, bio-oil, and biochar. Used for plastic waste, biomass, and municipal solid waste treatment.
• Plasma Gasification: Uses plasma torches creating temperatures above 3000°C to convert waste into syngas and inert slag. Can process hazardous and mixed waste streams effectively.
• Products: Syngas (mixture of H₂, CO, CH₄) can be used for electricity generation, as chemical feedstock, or converted to liquid fuels.
• Advantages: Significant waste volume reduction (up to 90%), minimal landfill requirement, energy recovery, and reduced greenhouse gas emissions compared to conventional incineration.
• Applications in India: Several pilot projects and commercial plants are being explored under Swachh Bharat Mission and Smart Cities initiatives for sustainable waste management.

Detailed Explanation:

Answer: Option 2 — 2 and 3 only

H-CNG (Hydrogen-enriched Compressed Natural Gas) is a blend of hydrogen and CNG that improves combustion efficiency and reduces emissions. While it significantly reduces carbon monoxide, carbon dioxide, and hydrocarbon emissions, it does not completely eliminate CO emissions since the blend still contains CNG. Additionally, hydrogen production and blending infrastructure make H-CNG more expensive than conventional CNG.

❌ Statement 1 – Incorrect: H-CNG significantly reduces but does not eliminate carbon monoxide emissions entirely, as the blend still contains CNG which produces some CO during combustion.
✅ Statement 2 – Correct: H-CNG reduces carbon dioxide and hydrocarbon emissions compared to conventional CNG due to improved combustion efficiency from hydrogen addition.
✅ Statement 3 – Correct: According to Indian government guidelines, hydrogen can be blended up to 18% by volume with CNG (approximately one-fifth), making this statement correct.
❌ Statement 4 – Incorrect: H-CNG is more expensive than CNG due to the costs associated with hydrogen production, storage infrastructure, and blending technology.

📝 Short Notes: Hydrogen-Enriched CNG (H-CNG)

• Composition: H-CNG is a blend of hydrogen (up to 18% by volume) with Compressed Natural Gas (CNG).
• Emission Benefits: Reduces CO, CO₂, HC, NOₓ and particulate matter emissions; improves air quality in urban areas.
• Combustion Efficiency: Hydrogen's high flame speed and wide flammability range improve combustion efficiency and reduce fuel consumption.
• Pilot Projects in India: H-CNG buses have been tested in Delhi as part of government initiatives to reduce vehicular pollution.
• Cost Factor: More expensive than CNG due to hydrogen production (electrolysis or steam methane reforming), storage, and distribution infrastructure requirements.
• Environmental Impact: Not zero-emission fuel (unlike pure hydrogen) but serves as a transitional cleaner alternative to conventional CNG.

Detailed Explanation:

Answer: Option 4 — 1, 2, 3 and 4

The burning of crop/biomass residue releases multiple pollutants into the atmosphere through incomplete combustion and chemical reactions. All four pollutants mentioned—carbon monoxide, methane, sulphur dioxide, and ozone—are associated with biomass burning, either as direct emissions or secondary formation.

✅ Carbon Monoxide (CO) – Released: Incomplete combustion of organic matter directly produces carbon monoxide, a toxic gas that reduces oxygen-carrying capacity in blood and contributes to air pollution.

✅ Methane (CH₄) – Released: Biomass burning releases methane, a potent greenhouse gas with 25 times the global warming potential of CO₂ over a 100-year period, contributing significantly to climate change.

✅ Ozone (O₃) – Formed: While not directly emitted, ozone forms as a secondary pollutant when nitrogen oxides (NOₓ) and volatile organic compounds (VOCs) from biomass burning react in the presence of sunlight, creating ground-level ozone.

✅ Sulphur Dioxide (SO₂) – Released: When biomass containing sulfur compounds burns, it releases sulphur dioxide, which causes respiratory problems and contributes to acid rain formation.

📝 Short Notes: Biomass Burning Emissions

• Primary Pollutants: Direct emissions include CO, CH₄, SO₂, NOₓ, particulate matter (PM2.5 and PM10), and black carbon
• Secondary Pollutants: Ground-level ozone forms when NOₓ and VOCs react in sunlight; acid rain forms from SO₂ and NOₓ reactions with water vapor
• Greenhouse Gases: Biomass burning releases CO₂, CH₄, and N₂O, contributing approximately 40% of global CO emissions and 20% of tropospheric ozone precursors
• Health Impacts: Particulate matter and toxic gases cause respiratory diseases, cardiovascular problems, and reduced visibility; CO interferes with oxygen transport in blood
• Environmental Impact: Contributes to air pollution, smog formation, acid deposition, soil nutrient loss, and climate change through greenhouse gas emissions
• Major Sources: Agricultural residue burning (stubble burning in Punjab/Haryana), forest fires, and traditional biomass fuel use for cooking and heating

Detailed Explanation:

Answer: Option 1 — 1 only

The Compensatory Afforestation Fund Management and Planning Authority (CAMPA) was established under the Compensatory Afforestation Fund Act, 2016, to manage funds collected for compensatory afforestation activities. The Act mandates the creation of both National CAMPA and State CAMPAs to ensure proper administration and utilization of these funds at respective levels. However, the Act does not explicitly mandate people's participation in compensatory afforestation programmes.

✅ Statement 1 – Correct: The Compensatory Afforestation Fund Act, 2016, establishes CAMPA at both National and State levels. National CAMPA oversees fund management at the national level, while State CAMPAs manage funds within their respective jurisdictions for compensatory afforestation activities.

❌ Statement 2 – Incorrect: The Compensatory Afforestation Fund Act, 2016, does not contain any explicit provision mandating people's participation in compensatory afforestation programmes. The Act primarily focuses on fund management, utilization mechanisms, and institutional structures rather than public participation requirements.

📝 Short Notes: Compensatory Afforestation Fund Management and Planning Authority (CAMPA)

• Legal Framework: Established under the Compensatory Afforestation Fund Act, 2016, to manage funds collected from forest land diverted for non-forest purposes.
• Two-Tier Structure: National CAMPA at the central level and State CAMPAs in each state/union territory for decentralized fund management.
• Fund Sources: Money collected from user agencies as Net Present Value (NPV) and compensatory afforestation charges when forest land is diverted.
• Fund Utilization: Used for compensatory afforestation, assisted natural regeneration, forest management, wildlife protection, and infrastructure development in forests.
• National CAMPA Composition: Chaired by the Union Minister of Environment, Forest and Climate Change, with members from various ministries and experts.
• State CAMPA Composition: Chaired by the Chief Minister of the state, with state forest officials and other relevant stakeholders.
• Key Objective: Ensure transparent and efficient utilization of funds for ecological restoration and conservation of forest resources.

Detailed Explanation:

Answer: Option 2 — 2 only

The Environment Protection Act, 1986 empowers the Central Government to lay down standards for emission or discharge of environmental pollutants but does not explicitly mandate public participation requirements. While public participation is important in environmental protection, it was introduced through subsequent EIA Notifications issued under the Act's authority.

❌ Statement 1 – Incorrect: The EPA, 1986 does not explicitly state requirements for public participation or the procedure and manner in which it is sought. These provisions were introduced later through EIA Notifications (1994, 2006) issued under the Act.

✅ Statement 2 – Correct: Section 3(2)(iv) of the Environment Protection Act, 1986 specifically empowers the Central Government to lay down standards for emission or discharge of environmental pollutants from various sources.

📝 Short Notes: Environment Protection Act, 1986

• Enactment: The Environment Protection Act was enacted in 1986 following the Bhopal Gas Tragedy (1984) to provide a comprehensive framework for environmental protection.
• Umbrella Legislation: It serves as an umbrella Act that provides a framework for coordination of activities of various central and state authorities under existing laws.
• Powers of Central Government (Section 3): Includes power to take measures to protect and improve environmental quality, lay down emission/discharge standards, restrict areas for industries, lay down procedures for handling hazardous substances, and examine manufacturing processes.
• Rule-making Power: The Act empowers the government to make rules for various aspects including standards for emissions, prohibition/restriction of handling hazardous substances, and procedures for environmental impact assessment.
• Public Participation: Not explicitly mentioned in the Act itself but incorporated through EIA Notifications issued under the Act's authority, particularly the 1994 and 2006 notifications which mandated public hearings for certain projects.
• Penalties: Provides for imprisonment up to 5 years and/or fine up to ₹1 lakh for violations, with additional fines for continuing violations.

Detailed Explanation:

Answer: Option 3 — The e-Waste Management and Handling Rules, 2011

Extended Producer Responsibility (EPR) was first introduced as a key feature in India through the e-Waste Management and Handling Rules, 2011. Under EPR, producers of electrical and electronic equipment are made responsible for the collection, channelization, and proper disposal of e-waste generated from their products after end-of-life. This principle was later extended to other waste management rules including the Plastic Waste Management Rules, 2016, but the e-Waste Rules of 2011 marked its first significant introduction in Indian environmental legislation.

📝 Short Notes: Extended Producer Responsibility (EPR) in India

• EPR Concept: Makes producers responsible for the entire lifecycle of their products, especially post-consumer waste management
• Objectives: Reduce environmental burden, promote circular economy, ensure proper waste disposal and recycling
• Implementation: Producers must establish collection mechanisms, collaborate with authorized recyclers, and meet specified collection targets
• Recent Developments: EPR certificates tradable on centralized portal; Digital tracking of waste collection

Detailed Explanation:

Answer: Option 1 — Neyyar, Peppara and Shendurney Wildlife Sanctuaries; and Kalakad Mundanthurai Tiger Reserve

The Agasthyamala Biosphere Reserve is located in the southern Western Ghats, spanning across Kerala and Tamil Nadu. It comprises three wildlife sanctuaries in Kerala (Neyyar, Peppara, and Shendurney) and the Kalakad Mundanthurai Tiger Reserve in Tamil Nadu, making Option 1 the correct answer. This biosphere reserve is recognized as one of the 18 hotspots of biological diversity in the world and serves as a genetic reservoir of cultivated and wild species, including many rare, endemic, and medicinal plants.

📝 Short Notes: Major Biosphere Reserves of India