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 11–20 of 259 questions
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UPSC 2025Environment and Ecology · Miscellaneous
Q11. Consider the following statements: Statement I: Circular economy reduces the emissions of greenhouse gases. Statement II: Circular economy reduces the use of raw materials as inputs. Statement III: Circular economy reduces wastage in the production process. Which one of the following is correct in respect of the above statements?
Explanation
Statement I is correct: The circular economy model aims to reduce resource extraction, encourage recycling and reuse, and design out waste. All these reduce energy consumption and emissions. Greenhouse gas (GHG) emissions are reduced in several ways:
Lower extraction and processing of virgin materials (which is carbon-intensive). Emphasis on reuse, recycling, and resource efficiency. Waste reduction leads to less landfill methane and less incineration. Impact organisation Circle Economy’s Circularity Gap Report 2021 finds that circular economy strategies can cut global greenhouse gas emissions by 39%.
Statement II is correct: By emphasizing reuse, refurbishment, remanufacturing, and recycling, the circular economy significantly reduces the need for raw materials as inputs in production processes, conserving natural resources.
Statement III is correct: The circular economy focuses on reducing wastage in production by improving process efficiency, redesigning products for durability and easy repair, and adopting sustainable manufacturing practices. Statements II and III explain Statement I: Reducing raw material use (Statement II) and cutting production wastage (Statement III) both contribute to lower energy consumption and fewer emissions, which leads to a reduction in overall greenhouse gas emissions (Statement I).
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: Circular economy do NOT reduces the use of raw materials as inputs." Denial would contradict the very essence of the circular economy. So denial is implausible, meaning S2 is true. Similarly apply this approach in all three statements and you can observe all are true and logically correct explanation of S1.
UPSC 2025Environment and Ecology · Pollution
Q12. Artificial way of causing rainfall to reduce air pollution makes use of
Explanation
Cloud-seeding is a technique used to modify weather by releasing silver iodide (AgI) into the atmosphere to facilitate the formation of ice crystals, enhancing the cloud’s ability to generate rain. In the process of cloud-seeding, chemicals like silver iodide, potassium iodide, and dry ice are dispersed into the sky via airplanes and helicopters.
Additional insight:
Cloud seeding is divided into two main types:
Hygroscopic Cloud Seeding: This approach promotes the growth of water droplets in liquid clouds by introducing salt particles, typically at the cloud’s base, which helps the droplets combine and become heavy enough to fall as rain. Glaciogenic Cloud Seeding: This method encourages the formation of ice crystals in supercooled clouds by releasing substances such as silver iodide or dry ice, which serve as ice nuclei, initiating ice formation and ultimately leading to precipitation.
UPSC 2025Environment and Ecology · Environmental Laws, Conventions and Policies
Q13. Which organization has enacted the Nature Restoration Law (NRL) to tackle climate change and biodiversity loss?
Explanation
The European Union has introduced the Nature Restoration Law (NRL) to address climate change and the loss of biodiversity. This law requires member countries to meet specific targets for restoring damaged ecosystems on both land and sea, forming a central part of the EU’s environmental strategy. Its goal is to rejuvenate nature throughout Europe, benefiting wildlife, the climate, and communities. If properly enforced, the law could have a transformative impact. It is now essential for both the European Parliament and EU member nations to approve and promptly implement the legislation.
Exam tip:
The word "enacted" implies legislative authority -- only bodies with law-making power can do this. Only the EU has the jurisdiction and institutional setup to actually enact a law like the Nature Restoration Law (NRL).
UPSC 2025Environment and Ecology · Climate Change
Q14. The World Bank warned that India could become one of the first places where wet-bulb temperatures routinely exceed 35°C. Which of the following statements best reflect(s) the implication of the above-said report? I. Peninsular India will most likely suffer from flooding, tropical cyclones and droughts. II. The survival of animals including humans will be affected as shedding of their body heat through perspiration becomes difficult. Select the correct answer using the code given below.
Explanation
Wet-bulb temperature is the lowest temperature that air can reach through the process of evaporation of water under current atmospheric conditions. It is measured by wrapping a thermometer bulb in a wet cloth and exposing it to air flow; as water evaporates from the cloth, it cools the thermometer, and the resulting temperature is the wet-bulb temperature.
Statement 1 is incorrect: Flooding, tropical cyclones and droughts in the Peninsular India are significant impacts of climate change. These are not the direct implications of the wet-bulb temperatures exceeding 35°C. The World Bank’s warning in its report titled Climate Investment Opportunities in India’s Cooling Sector, specifically relates to heat and humidity, not to hydrometeorological events like floods or cyclones.
Statement 2 is correct: This statement directly reflects the core implication of the World Bank’s report titled "Climate Investment Opportunities in India’s Cooling Sector". At wet-bulb temperatures above 35°C, humans and animals cannot cool themselves through sweating, leading to life-threatening conditions.
Additional insight:
Wet-bulb temperature reflects both heat and humidity in the air. When relative humidity is high, less evaporation occurs, so the wet-bulb temperature is closer to the actual air temperature. When humidity is low, more evaporation happens, making the wet-bulb temperature much lower than the air temperature. At 100% relative humidity, the wet-bulb and air temperatures are equal because no more evaporation can occur. Wet-bulb temperature is important because it indicates the limit at which humans and animals can cool themselves by sweating. If the wet-bulb temperature rises above 35°C, the body can no longer shed heat effectively, making survival difficult even for healthy individuals.
UPSC 2024Environment and Ecology · Biodiversity
Q15. The organisms "Cicada, Froghopper, and Pond skater" are:
Explanation
The organisms Cicada, Froghopper, and Pond Skater are all insects. They belong to the class Insecta within the phylum Arthropoda. Cicadas are insects belonging to the order Hemiptera. They are known for their loud, distinctive calls and long life cycles with some species spending years underground as nymphs before emerging as adults. Froghoppers are also insects in the order Hemiptera. They are known for their jumping ability and the foam-like "cuckoo spit" produced by their nymphs. Pond skaters (also called water striders) are insects in the order Hemiptera. They are known for their ability to walk on water due to surface tension and their hydrophobic legs. (a) Cicada (b) Froghopper (c) Pond skater Fig: (a) Cicada, (b) Froghopper, and (c) Pond skater
Exam tip:
Froghopper, Association: Has "hopper" in its name implies jumping. Similar to grasshopper, planthopper. Pond skater, Association: Seen gliding over water surface. Thin-legged, fast-moving -- does not sink. You’d recall this from schoolbooks or ponds. If it hops, skates, or buzzes-- it’s almost always an insect.
UPSC 2024Environment and Ecology · Pollution
Q16. With reference to perfluoroalkyl and polyfluoroalkyl substances (PFAS) that are used in making many consumer products, consider the following statements: 1. PFAS are found to be widespread in drinking water, food and food packaging materials. 2. PFAS are not easily degraded in the environment. 3. Persistent exposure to PFAS can lead to bioaccumulation in animal bodies. Which of the statements given above are correct?
Explanation
Per- and polyfluoroalkyl substances (PFAS) are a large, complex group of synthetic chemicals that have been used in consumer products around the world since about the 1950s.
Statement 1 is correct: People are most likely exposed to these chemicals by consuming PFAS-contaminated water or food, using products made with PFAS, or breathing air containing PFAS. Although PFOS use has been phased out, it can still be found in drinking water, groundwater, soil, and air.
Statement 2 is correct: PFAS molecules have a chain of linked carbon and fluorine atoms. Because the carbon-fluorine bond is one of the strongest, these chemicals do not degrade easily in the environment, leading to long-term contamination.
Statement 3 is correct: PFAS can accumulate in the bodies of animals, including humans, through persistent exposure. They tend to concentrate in organs like the liver and kidneys and bio-accumulate up the food chain
UPSC 2024Environment and Ecology · Pollution
Q17. Consider the following statements: Statement-I: Many chewing gums found in the market are a source of environmental pollution. Statement-II: Many chewing gums contain plastic as gum base. Which one of the following is correct in respect of the above statements?
Explanation
Statement I is correct: Chewing gum contributes significantly to environmental pollution due to its non-biodegrad-able nature. Most chewing gums are improperly disposed of, leading to litter on streets and microplastic pollution in water bodies.
Statement II is correct: Modern chewing gums often use synthetic polymers, such as polyethylene and polyvinyl acetate, as part of their gum base, which are essentially plastics. These materials do not biodegrade easily, causing long-lasting environmental harm. The presence of plastic in gum makes it non-biodegradable and a significant contributor to pollution when improperly disposed of. Hence, Both Statement-I and Statement-II are correct and Statement-II explains Statement-I
UPSC 2024Environment and Ecology · Environmental Laws, Conventions and Policies
Q18. Consider the following statements: Statement-I: The Indian Flying Fox is placed under the "vermin" category in the Wild Life (Protection) Act, 1972. Statement-II: The Indian Flying Fox feeds on the blood of other animals. Which one of the following is correct in respect of the above statements?
Explanation
Note: Vermin category listed in Schedule V of the Wild-life Protection Act, 1972 has been removed after the Wildlife Protection Amendment Act 2022, as now there are only 4 schedules in WPA. Hence the answer is subject to considerations made by the Commission.
Statement 1 is correct: The Indian Flying Fox is placed under the "vermin" category in the Wild Life (Protection) Act, 1972 due to its destructive tendencies towards fruit farms.
Statement 2 is incorrect: Bats are the only flying mammals in the world, and the Indian Flying Fox is one of the largest. The species, Pteropus giganteus, also called the Great Indian Fruit Bat, eats fruits, feeding on the juice, and helps in seed dispersion and pollination, making them an integral part of the ecosystem.
Additional insight:
The Wild Life (Protection) Act, 1972, is an important environmental legislation in India aimed at protecting wildlife, conserving biodiversity, and regulating the trade of wild animals and their products. Some key changes done through Wild life (Protection) Amendment Act, 2022 are:
Aligned the Act with the Convention on International Trade in Endangered Species (CITES). Reduced the number of schedules for animals from six to four. The Wild Life (Protection) Amendment Act, 2022 removed the schedule listing vermin species from the original Wild Life (Protection) Act, 1972. Previously, Schedule V of the Act designated certain species as vermin, allowing them to be hunted freely. The 2022 Amendment streamlined the schedules, eliminating the separate vermin category.
UPSC 2024Environment and Ecology · Environmental Laws, Conventions and Policies
Q19. According to the Environmental Protection Agency (EPA), which one of the following is the largest source of sulphur dioxide emissions?
Explanation
Emissions that lead to high concentrations of SO₂ generally also lead to the formation of other SOx. The largest sources of SO₂ emissions are from fossil fuel combustion at power plants and other industrial facilities. EPA’s national ambient air quality standards for SO₂ are designed to protect against exposure to the entire group of sulfur oxides (SOx). SO₂ is the component of greatest concern and is used as the indicator for the larger group of gaseous sulfur oxides (SOx). Other gaseous SOx (such as SO₃) are found in the atmosphere at concentrations much lower than SO₂.
UPSC 2024Environment and Ecology · Environmental Laws, Conventions and Policies
Q20. Consider the following statements: Statement I: India does not import apples from the United States of America. Statement II: In India, the law prohibits the import of Genetically Modified food without the approval of the competent authority. Which one of the following is correct in respect of the above statements?
Explanation
Statement-I is incorrect: Apples are one of the major imports from the USA. After India removed "retaliatory import duty" on US apples in September, imports of American apples have surged 40 times in three months, while traders are hopeful of regaining market share. In 2017-18, the import of US apples was a record of over 7 million boxes, which dropped to 50,000 boxes in the 2022-23. Statement-II is correct: In India, the Food Safety and Standards Act, 2006, prohibits import, manufacture, use or sale of GM food without FSSAI’s approval.
Additional insight:
Food Safety and Standards Authority of India (FSSAI) is a statutory body established under the Food Safety and Standards Act, 2006 (FSSA). It functions under the Ministry of Health & Family Welfare, Government of India and is responsible for ensuring food safety and regulating food standards in India.
Exam tip:
For S1, "Import no apple from USA" is too extreme to be true. Even when someone brought a kg apple from USA, this statement will becomes false, hence option C is correct.
Answer key for these questions
Q
UPSC year
Correct answer
11
2025
(a) Both Statement II and Statement III are correct and both of them explain Statement I
12
2025
(a) silver iodide and potassium iodide
13
2025
(a) The European Union
14
2025
(b) II only
15
2024
(c) Insects
16
2024
(d) 1, 2 and 3
17
2024
(a) Both Statement-I and Statement-II are correct and Statement-II explains Statement-I
18
2024
(c) Statement -I is correct, but Statement-II is incorrect
19
2024
(d) Power plants using fossil fuels
20
2024
(d) Statement-I is incorrect, but Statement-II is correct.
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.
