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 121–130 of 259 questions
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UPSC 2018Environment and Ecology · Pollution
Q121. Which of the following is/are the possible consequence/s of heavy sand mining in river beds? 1. Decreased salinity in the river 2. Pollution of groundwater 3. Lowering of the water-table Select the correct answer using the code given below:
Explanation
Sand mining is the extraction of sand, mainly through an open pit (or sandpit) but sometimes mined from beaches and inland dunes or dredged from ocean and river beds.
Statement 1 is incorrect: Sand mining typically does not directly affect the salinity of the river. Salinity is more influenced by factors like the influx of seawater in coastal areas, evaporation rates, and the presence of saline minerals in the riverbed.
Statement 2 is correct: The amount of suspended particles in the water at the excavation site and downstream increases due to increased riverbed and bank erosion. This process stirs up the sediments and increases the chance of contamination of groundwater.
Statement 3 is correct: Heavy sand mining causes removal of sand and gravels from the riverbed. Due to this the groundwater table drops leaving the drinking water wells on the embankments of these rivers dry. Alteration of rivers, damage to river biodiversity, altered sediment budget lead to poor water quality, worsen water scarcity threat to coastal communities, damage to public and private property.
UPSC 2018Environment and Ecology · Environmental Laws, Conventions and Policies
Q122. Consider the following statements: 1. The definition of "Critical Wildlife Habitat" is incorporated in the Forest Rights Act, 2006. 2. For the first time in India, Baigas have been given Habitat Rights. 3. Union Ministry of Environment, Forest and Climate Change officially decides and declares Habitat Rights for Primitive and Vulnerable Tribal Groups in any part of India. Which of the statements given above is/are correct?
Explanation
Statement 1 is correct: Critical Wildlife Habitats (CWH) are defined under the Scheduled Tribes and Other Traditional Forest Dwellers (Recognition of Forest Rights) Act, 2006.. These are areas within wildlife sanctuaries and national parks that are critical for the survival of wildlife species and where human activities may be restricted.
Statement 2 is correct: The Baiga tribe in Madhya Pradesh was one of the first communities in India to be granted Habitat Rights under the Forest Rights Act, 2006. This recognition ensures their right to live in and sustainably use forest resources in their traditional habitats.
Statement 3 is incorrect: The declaration of Habitat Rights is the responsibility of the Ministry of Tribal Affairs and state-level authorities under the framework of the Forest Rights Act, 2006.
Exam tip:
For S3, aligns with Function-person/organisation/ministry match trap as its easy to manipulate to make it false. Isn’t it should be Tribal affairs ministry??
UPSC 2018Environment and Ecology · Environmental Laws, Conventions and Policies
Q123. How is the National Green Tribunal (NGT) different from the Central Pollution Control Board (CPCB)? 1. The NGT has been established by an Act whereas the CPCB has been created by an executive order of the Government. 2. The NGT provides environmental justice and helps reduce the burden of litigation in the higher courts whereas the CPCB promotes cleanliness of streams and wells, and aims to improve the quality of air in the country. Which of the statements given above is/are correct?
Explanation
The NGT provides environmental justice and Central Pollution Control Board (CPCB) NGT was established by National Green Tribunal Act, 2010, with jurisdiction over all civil disputes addressing important environmental issues. Central Pollution Control Board (CPCB) was established under the Water (Prevention and Control of Pollution) Act of 1974 as a statutory body. National Green Tribunal Act, 2010 was enacted for effective and expeditious disposal (within 6 months of appeal) of environmental cases and to help reduce burden of litigation in the higher courts. It is also entrusted with the powers & functions under the Air (prevention and control of pollution) Act, 1981. It provides for Enforcement of legal environmental rights, relief & compensation for damages caused. It works under the Ministry of Environment, Forest & Climate Change (MoEF&CC). The tribunal’s decision is enforceable as a civil court judgement and is governed by natural justice principles.
Statement 1 is incorrect: Both the NGT and CPCB were established by some Acts, namely, the NGT Act, 2010 and the Water (Prevention and Control of Pollution) Act, 1974, respectively.
Statement 2 is correct: The objective of NGT is to provide effective & expeditious disposal (within 6 months of appeal) of the environmental cases and to help reduce the burden of litigation in the higher courts.
UPSC 2018Environment and Ecology · Environmental Laws, Conventions and Policies
Q124. With reference to the ‘Global Alliance for Climate-Smart Agriculture (GACSA)’, which of the following statements is/are correct? 1. GACSA is an outcome of the Climate Summit held in Paris in 2015. 2. Membership of GACSA does not create any binding obligations. 3. India was instrumental in the creation of GACSA. Select the correct answer using the code given below:
Explanation
Global Alliance for Climate-Smart Agriculture (GACSA) is an inclusive, voluntary and action-oriented multi-stakeholder platform on Climate-Smart Agriculture (CSA). The vision is to improve food security, nutrition and resilience in the face of climate change. GACSA aims to catalyze and help create transformational partnerships to encourage actions that reflect an integrated approach to the three pillars of CSA.
Statement 1 is incorrect: The concept of Climate-Smart Agriculture (CSA) was originally developed by FAO and officially presented at the Hague Conference on Agriculture, Food Security and Climate Change in 2010, through the paper "Climate-Smart Agriculture: Policies, Practices and Financing for Food Security, Adaptation and Mitigation". The Global Alliance for Climate-Smart Agriculture (GACSA) was launched during the UN Climate Summit of 2014, in New York(not at the Paris Climate Summit in 2015).
Statement 2 is correct: Its membership does not impose any binding obligations on its participants, allowing for flexible engagement in promoting climate-smart agricultural practices.
Statement 3 is incorrect: While India is a signatory to the Global Alliance for Climate-Smart Agriculture (GACSA), India had no instrumental role in the creation of GACSA.
UPSC 2018Environment and Ecology · Environmental Organisations
Q125. The Partnership for Action on Green Economy (PAGE), a UN mechanism to assist countries transition towards greener and more inclusive economies, emerged at
Explanation
Partnership for Action on Green Economy (PAGE) is a direct response to the Rio+20 Declaration, The Future We Want i.e. The United Nations Conference on Sustainable Development 2012, Rio de Janeiro. PAGE serves as a framework to coordinate UN efforts in the green economy and to help nations meet and track the upcoming Sustainable Development Goals. The partnership aims to place sustainability at the core of economic policies and practices, thereby advancing the 2030 Agenda for Sustainable Development. It supports countries in reshaping their economic policies around sustainability to foster growth, create jobs, reduce poverty and inequality, and strength-en ecological foundations.
UPSC 2018Environment and Ecology · Environmental Organisations
Q126. "Momentum for Change: Climate Neutral Now" is an initiative launched by
Explanation
The UNFCCC Secretariat introduced the "Climate Neutral Now" initiative in 2015 to promote voluntary action towards climate neutrality. In 2016, during the UN Climate Change Conference in Marrakech (COP22), the UNFCCC Secretariat combined its "Climate Neutral Now" initiative with the "Momentum for Change" initiative, creating a new pillar focused on climate neutrality. The initiative aims to achieve a climate-neutral world by 2050, as outlined in the Paris Agreement. It provides a platform for recognizing and showcasing successful climate actions by non-Party stakeholders, including businesses, investors, cities, regions, and civil society.
UPSC 2018Environment and Ecology · Protected Areas for the Biodiversity Conservation
Q127. In which one of the following States is Pakhui Wildlife Sanctuary located?
Explanation
Pakke Tiger Reserve is also known as "Pakhui Tiger Re-serve". It is situated in the East Kameng district of Arunachal Pradesh, India. It is one of the key protected areas in the Eastern Himalayas and is renowned for its rich biodiversity. The reserve lies within the Eastern Himalayan biodiversity hotspot, an area known for its diverse flora and fauna. Pakhui is home to a significant population of Royal Bengal tigers, along with Asian elephants, clouded leopards, Hoolock gibbons, and a variety of bird species, including the endangered Great Indian hornbill. For its Hornbill Nest Adoption Program, this Tiger Reserve received the 2016 India Biodiversity Award in the category of "Conservation of vulnerable species."
UPSC 2018Environment and Ecology · Species
Q128. Why is a plant called Prosopis juliflora often mentioned in the news?
Explanation
Prosopis juliflora, or mesquite, is a leguminous flowering plant native to South America. It has become invasive in regions like India, Africa, and the Middle East, where it competes with native species for water and nutrients, threatening local bio-diversity.
UPSC 2017Environment and Ecology · Ecology, Ecosystem and Functions of Ecosystem
Q129. The term ‘M-STrIPES’ is sometimes seen in the news in the context of
Explanation
MSTrIPES stands for Monitoring system for Tigers - Intensive Protection and Ecological Status.M-STrIPES was launched in 2010 by NTCA and WII across Indian tiger reserves. It is a software-based monitoring system, designed to assist wild-life protection. The system consists of two components:
Field based methods for ecological monitoring, law enforcement, recording wildlife offences, and patrolling. A specialised GIS application for reporting, analysis, and data storage. Forest guards are required to use a GPS to track their movements as part of MSTrIPES, in addition to entering their observations on site-specific data sheets.
UPSC 2017Environment and Ecology · Biodiversity
Q130. Due to some reasons, if there is a huge fall in the population of species of butterflies, what could be its likely consequence/consequences? 1. Pollination of some plants could be adversely affected. 2. There could be a drastic increase in the fungal infections of some cultivated plants. 3. It could lead to a fall in the population of some species of wasps, spiders and birds. Select the correct using the code given below:
Explanation
Transfer of pollen grains (shed from the anther) to the stigma of a pistil is termed pollination. Flowering plants have evolved an amazing array of adaptations to achieve pollination. Depending on the source of pollen, pollination is divided into three types, i. e. Autogamy, Geitonogamy and Xenogamy.
Statement 1 is correct: Butterflies are important pollinators for many flowering plants. Plant species particularly those that produce brightly colored, scented flowers with deep nectar tubes are adapted to butterfly pollination. A drastic fall in butterfly populations would result in reduced pollination, affecting plant reproduction and possibly leading to a decline in the population of such plant species.
Statement 2 is incorrect: There is no direct link between butterfly populations and fungal infections in cultivated plants. Fungal infections are influenced by factors like humidity, temperature, plant health, and soil conditions rather than by the presence or absence of butterflies.
Statement 3 is correct: Butterflies form a crucial part of the food chain, serving as prey for birds, wasps, spiders, and other insectivores. Many species of small birds (e.g., flycatch-ers, warblers, bee-eaters) depend on butterflies and their larvae (caterpillars) as a major food source. If butterfly populations decline then predators depending on them may suffer a population decline.
Exam tip:
S1 and S3 contains "some" and "Some" = possibility logic, not absolute. If even one species of organism does something, the statement is likely correct. While S2 contains an exaggerated phrase, "Drastic Increase", which is too hard to prove and more probable to be false.
Answer key for these questions
Q
UPSC year
Correct answer
121
2018
(b) 2 and 3 only
122
2018
(a) 1 and 2 only
123
2018
(b) 2 only
124
2018
(b) 2 only
125
2018
(b) The United Nations Conference on Sustainable Development 2012, Rio de Janeiro
126
2018
(c) The UNFCCC Secretariat
127
2018
(a) Arunachal Pradesh
128
2018
(b) It tends to reduce the biodiversity in the area in which it grows.
129
2017
(b) Maintenance of Tiger Reserves
130
2017
(c) 1 and 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.
