Environment and Ecology: UPSC Previous Year Questions (Prelims)
259 previous year UPSC Prelims Environment and Ecology questions are on this page, from 1996 to 2025, in 10 chapters. Species, Pollution, Environmental Laws and Conventions and Climate Change are the largest, and recent papers lean on statement-pairs about news items: Direct Air Capture, the Nature Restoration Law, PFAS and the Peacock tarantula. Filter by chapter to revise one area, or by year for a single paper.
Explanations state facts as of the year each question was asked; words like “recently” refer to that year.
Showing 101–110 of 259 questions
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UPSC 2019Environment and Ecology · Pollution
Q101. Consider the following: 1. Carbon monoxide 2. Methane 3. Ozone 4. Sulphur dioxide Which of the above are released into the atmosphere due to the burning of crop/biomass residue?
Explanation
Burning stubble (parali) is the process of removing crop residue from the field in order to prepare it for the next crop. Open stubble burning releases a lot of harmful pollutants into the air, including smoke, particles, greenhouse gases (CO₂, N₂O, O₃ CH₄), air pollutants (CO, NH₃, NOx, SO₂, NMHC), and volatile organic compounds. These pollutants are dangerous to human health. Husk burning reduces the fertility of the soil by destroying its nutrients. When stubble burns, heat is produced that permeates the soil, causing the loss of moisture and beneficial microbes.
Exam tip:
You can try, The "NOT" approach for all statements, this tests the improbability of negating a statement--if denying its impact seems highly unlikely, the statement is plausibly true. For Example: CO or O₃ are NOT released in crop burning? Absurd, unlikely.
UPSC 2019Environment and Ecology · Climate Change
Q102. In the context of which of the following do some scientists suggest the use of cirrus cloud thinning technique and the injection of sulphate aerosol into the stratosphere?
Explanation
There is a renewed interest in two dominant methods of geoengineering such as stratospheric sulphate aerosol increase and cirrus cloud thinning aims to reduce global warming effects. Geoengineering, often known as climate intervention, is the deliberate and extensive modification of the Earth’s climatic system with the intention of reducing global warming. The stratosphere can be injected with sulphate aerosol particles to block some of the sun’s rays and possibly cool the planet. Sulphur droplets are good at scattering the sun’s light back out into space and it does not heat the stratosphere as much as other aerosols.
UPSC 2019Environment and Ecology · Climate Change
Q103. Consider the following statements: 1. Agricultural soils release nitrogen oxides into the environment. 2. Cattle release ammonia into the environment. 3. Poultry industry releases reactive nitrogen compounds into the environment. Which of the statements given above is/are correct?
Explanation
As per the Indian Nitrogen Assessment report, 2017, the share of agriculture in total GHG emissions has gradually declined from 28% in 1994 to 14% in 2016. Agricultural emissions in India are primarily from the livestock sector (54.6%) and the use of nitrogenous fertilizers (19%). Rice cultivation in anaerobic conditions accounts for a major portion of agricultural emissions (17.5%).
Statement 1 is correct: Agricultural soils release nitrogen oxides into the environment Fertilizers (especially nitrogen-based like urea) lead to the emission of nitrous oxide (N₂O), a greenhouse gas. Microbial processes such as nitrification and denitrification release NO, NO, and NO.
Statement 2 is correct: Cattle release ammonia into the environment Cattle excrete urea in urine, which breaks down into ammonia (NH₃) through microbial action. Livestock farming is a major contributor to ammonia emissions.
Statement 3 is correct: Poultry industry releases reactive nitrogen compounds into the environment Poultry litter (manure, bedding material, and feed waste) contains nitrogen compounds that can convert into ammonia, nitrates, and nitrites. This contributes to air and water pollution.
UPSC 2019Environment and Ecology · Climate Change
Q104. In the context of proposals to the use of hydrogen-enriched CNG (H-CNG) as fuel for buses in public transport, consider the following statements: 1. The main advantage of the use of H-CNG is the elimination of carbon monoxide emissions. 2. H-CNG as fuel reduces carbon dioxide and hydrocarbon emissions. 3. Hydrogen up to one-fifth by volume can be blended with CNG as fuel for buses. 4. H-CNG makes the fuel less expensive than CNG. Which of the statements given above is/are correct?
Explanation
Hydrogen-enriched CNG (H-CNG) is a blended gas. It is produced by mixing hydrogen with CNG. HCNG reduces emissions of CO up to 70% and engines can be calibrated to release lower amounts of NO. enables up to 5 % savings in fuel. It can be the first step towards the future Hydrogen economy. It gives better performance due to higher Octane rating of H2.
Statement 1 is incorrect: HCNG doesn’t eliminate but reduces emissions of CO up to 70%.
Statement 2 is correct: It can be used in place of gasoline, diesel fuel and propane (C3H8) / LPG and its combustion produces fewer undesirable gases.
Statement 3 is correct: The blending of hydrogen with CNG provides a blended gas termed as HCNG. Also, the ideal Hydrogen concentration is close to 20 %. It can prove to be the ideal fuel for heavy-duty vehicles and applications with high loads.
Statement 4 is incorrect: The current cost of Hydrogen is more than the cost of Natural Gas. So, HCNG’s cost is more than CNG.
Exam tip:
When S2 says "Reduces", then, isn’t S1’s "Elimination of CO" an extreme phrase, hence S1 is more probable to be false, Also, what do you think is more practical and logical: Elimination or Reducing? Clearly Second one hence S1 false and S2 true giving option B as correct.
UPSC 2019Environment and Ecology · Environmental Laws, Conventions and Policies
Q105. Consider the following statements: 1. As per recent amendment to the Indian Forest Act, 1927, forest dwellers have the right to fell the bamboos grown in forest areas. 2. As per the Scheduled Tribes and Other Traditional Forest Dwellers (Recognition of Forest Rights) Act, 2006, bamboo is a minor forest produce. 3. The Scheduled Tribes and Other Traditional Forest Dwellers (Recognition of Forest Rights) Act, 2006 allows ownership of minor forest produce to forest dwellers. Which of the statements given above is/are correct?
Explanation
Statement 1 is incorrect: The Indian Forest Act, 1927, was amended in 2017 to exclude bamboo grown on non-forest land from the definition of "tree," thereby allowing its free cultivation and transportation. However, this amendment does not grant forest dwellers the right to fell bamboo grown on forest areas. Bamboo in forest areas is still regulated under forest laws.
Statement 2 is correct: The Forest Rights Act (FRA) of 2006 recognizes bamboo as a minor forest produce (MFP).
Statement 3 is correct: The FRA, 2006, grants forest dwellers the right to own, collect, use, and dispose of minor forest produce (MFP). This includes bamboo, tendu leaves, honey, and other non-timber forest products.
Additional insight:
The National Bamboo Mission (NBM) in India, initiated by the Ministry of Agriculture and Farmers Welfare, seeks to enhance the bamboo sector’s growth. It aims to expand bamboo plantations, improve post-harvest management, promote product development, and rejuvenate the industry, supporting nurseries, cultivation, and processing units.
UPSC 2019Environment and Ecology · Environmental Laws, Conventions and Policies
Q106. In India, ‘extended producer responsibility’ was introduced as an important feature in which of the following?
Explanation
Laws to manage e-waste have been in place in India since
2011 under The e-Waste (Management and Handling) Rules, 2011, which was amended in 2016 as E-waste (Management) Rules, 2016. It recognises producers’ liability for recycling and reducing e-waste in the country. Extended Producer Responsibility (EPR) is a policy approach under which producers are given a significant responsibility - financial and/or physical - for the treatment or disposal of post-consumer products. The Central Pollution Control Board (CPCB) has been given the Extended Producer Responsibility (EPR) authorisation under the new e-waste rules.
UPSC 2019Environment and Ecology · Environmental Laws, Conventions and Policies
Q107. Consider the following statements: 1. As per law, the Compensatory Afforestation Fund Management and Planning Authority exists at both National and State levels. 2. People’s participation is mandatory in the compensatory afforestation programmes carried out under the Compensatory Afforestation Fund Act, 2016. Which of the statements given above is/are correct?
Explanation
Compensatory Afforestation Fund Act (Campa Act), 2016 is aimed at providing an appropriate institutional mechanism to utilize afforestation funds. The Act sets up the Central and State Compensatory Afforestation Fund Management & Planning Authorities (CAMPA).
Statement 1 is correct: As per the Act, the Compensatory Afforestation Fund Management and Planning Authority (CAMPA) is set up at both central and state levels for expeditious and transparent utilisation of funds released for forest land diverted for non-forest purposes. The National Fund receives 10% & State Fund gets 90% of funds collected.
Statement 2 is incorrect: The Compensatory Afforestation Fund Act, 2016 does not mandate people’s participation in compensatory afforestation programmes. While community involvement is encouraged in forest conservation efforts, the Act does not legally require it.
UPSC 2019Environment and Ecology · Environmental Laws, Conventions and Policies
Q108. Consider the following statements: The Environment Protection Act, 1986 empowers the Government of India to: 1. State the requirement of public participation in the process of environmental protection, and the procedure and manner in which it is sought 2. Lay down the standards for emission or discharge of environmental pollutants from various sources Which of the statements given above is/are correct?
Explanation
Environment (Protection) Act, 1986 is aimed at protecting, improving the environment & reducing pollution. The Act, empowers the Government of India for coordination of action by the state, planning and execution of nationwide programmes. The Act authorises the central government to control & reduce pollution from all sources.
Statement 1 is incorrect: The provisions in the Environment (Protection) Act, 1986 does not explicitly mention detailed provisions for public participation. However, it does enable certain mechanisms that indirectly promote public involvement.
Statement 2 is correct: Section 3(2)(v) of the Act states that the central government can prescribe standards for the quality of the environment and emissions or discharges of pollutants from various sources. The Act also allows the government to regulate industrial and commercial activities that may harm the environment.
UPSC 2019Environment and Ecology · Environmental Laws, Conventions and Policies
Q109. As per the Solid Waste Management Rules, 2016 in India, which one of the following statements is correct?
Explanation
Solid Waste Management Rules, 2016 promote the use of compost, conversion of waste into energy, and revision of parameters for landfills location and capacity. It replaced the Municipal Solid Wastes (Management and Handling) Rules, 2000 and are now applicable beyond municipal areas and have included urban agglomerations, census towns, notified industrial townships etc.
Option (a) is incorrect: Waste generators would now have to now segregate waste into three streams-Biodegradables, Dry (Plastic, Paper, Metal, Wood, etc.) and Domestic Hazardous waste (diapers, napkins, mosquito repellants, cleaning agents etc.) before handing it over to the collector.
Option (b) is incorrect: Under the Solid Waste Management Rules 2016, waste processing facilities will have to be set up by all local bodies having 1 million or more population within two years. In case of census towns below 1 million population, setting up common, or standalone sanitary landfills by, or for all local bodies having 0.5 million or more population and for setting up common, or regional sanitary landfills by all local bodies and census towns under 0.5 million population will have to be completed in three years.
Option (c) is correct: The new rules emphasize waste segregation at source, manufacturer responsibility for packaging and sanitary waste, and user fees for waste management. Biodegradable waste should be processed on-site through composting or bio-methanation, with residual waste handed over to authorized collectors. Schedule I of rules outlines criteria for landfill and waste processing site selection.
Option (d) is incorrect: As per the Solid Waste Management Rules, 2016, it is not mandatory for the waste generator that the waste generated in one district cannot be moved to another district.
UPSC 2019Environment and Ecology · Protected Areas for the Biodiversity Conservation
Q110. Consider the following statements: 1. Under Ramsar Convention, it is mandatory on the part of the Government of India to protect and conserve all the wetlands in the territory of India. 2. The Wetlands (Conservation and Management) Rules, 2010 were framed by the Government of India based on the recommendations of Ramsar Convention. 3. The Wetlands (Conservation and Management) Rules, 2010 also encompass the drainage area or catchment regions of the wetlands as determined by the authority. Which of the statements given above is/are correct?
Explanation
Statement 1 is incorrect: The Government of India is not obligated to protect and conserve all the wetlands within its territory. It is only obligated to conserve the wetlands that are recognised under the Ramsar convention as Ramsar sites.
Statement 2 is incorrect: The Wetlands (Conservation and Management) Rules, 2010, notified by the Ministry of Environment and Forest, aim to conserve and manage wetlands in India and prevent their degradation. However, they were not based on the Ramsar Convention’s recommendations. Its objectives are wetland conservation, protection, and management to prevent further degradation of wetlands in India.
Statement 3 is correct: As per Wetlands (Conservation and Management) Rules, 2010 a wetland includes natural or artificial areas of marsh, fen, peatland, or water, with static or flowing water, fresh, brackish, or salt, and marine areas with a depth at low tide not exceeding six meters. It also covers inland waters such as lakes, reservoirs, tanks, backwaters, lagoons, creeks, estuaries, and man made wetlands, along with their drainage areas or catchment regions.
Exam tip:
Mandatory is an absolute requirement. Rarely things are "Mandatory" on sovereign governments. Hence S1 is likely false. Eliminate options A and D.
Answer key for these questions
Q
UPSC year
Correct answer
101
2019
(d) 1, 2, 3 and 4
102
2019
(d) Reducing the global warming
103
2019
(d) 1, 2 and 3
104
2019
(b) 2 and 3 only
105
2019
(b) 2 and 3 only
106
2019
(c) The e-Waste (Management and Handling) Rules, 2011
107
2019
(a) 1 only
108
2019
(b) 2 only
109
2019
(c) The Rules provide for exact and elaborate criteria for the identification of sites for landfills and waste processing facilities.
110
2019
(c) 3 only
What UPSC has tested in Environment and Ecology
Species questions ask for classification and habitat: which is an insect, a filter feeder, or not a bird, and where an animal is found.
Law and convention questions ask which body or instrument covers what, such as the Wildlife Protection Act’s schedules, the e-Waste Rules and the Ramsar Convention.
Climate questions in 2025 covered Article 6 of the Paris Agreement, COP28, Direct Air Capture and wet-bulb temperatures.
Protected-area questions combine locations with distinctive features, such as the swamp park of Keibul Lamjao and Critical Tiger Habitats.
Frequently asked questions
How many previous year UPSC questions are there on Environment and Ecology?
This page covers 259 previous year UPSC Prelims GS Paper-I questions on Environment and Ecology, asked from 1996 to 2025. Each has the correct answer and an explanation.
Which Environment chapters have the most questions?
Species has the most with 43 questions, followed by Pollution and Environmental Laws, Conventions and Policies with 39 each, and Climate Change with 30. Environmental Organisations and Miscellaneous are the smallest.
How can I revise Environment and Ecology using these questions?
Take a chapter at a time with the Chapter filter, attempt the questions and read the facts UPSC has tested. Revise Species and Protected Areas with a map and a list of national parks at hand.
Are the 2025 Environment questions included?
Yes. The 2025 paper’s Environment questions on activated carbon, cement emissions, COP28, Article 6, Direct Air Capture, the Gooty tarantula, plastics and the Nature Restoration Law are included with full explanations.
