UPSC Prelims 2022 Environment questions: topic-wise weightage
UPSC Prelims 2022 asked 18 environment questions in GS Paper I, spread over 5 topics. See the environment weightage for 2022 below, then attempt each question with the official answer and an explanation.
Environment 2022: questions by topic
- Ecology and ecosystems3
- Biodiversity and species5
- Protected areas and conservation2
- Climate change and international conventions3
- Pollution, environmental laws and green technology5
Counted from the 18 questions on this page, tagged by topic in the Battle IAS PYQ bank.
Seeing 18 Environment questions spread over 5 topics can feel overwhelming. That's exactly why the Battle IAS PYQ Book maps every question topic by topic, so you know what to study first. Download free sample
Ecology and ecosystems 3
“If rainforests and tropical forests are the lungs of the Earth, then surely wetlands function as its kidneys.” Which one of the following functions of wetlands best reflects the above statement ?
Answer (d) & explanation
Absorbing heavy metals and excess nutrients is the kidney function (d). Kidneys filter waste out of the blood. Wetlands do the same for water: their aquatic plants, microbes and sediments take up heavy metals and excess nutrients, such as nitrates and phosphates, before the water moves on. That is why they are called the "kidneys of the landscape". Options (a), (b) and (c) are true of wetlands, describing the water cycle, the food web and sediment balance, but they are not "filtering" functions.
Notice that East Kolkata Wetlands, a Ramsar site, treat much of the city's sewage naturally while supporting fisheries. Wetlands also control floods and store carbon. India has rules under the Wetlands (Conservation and Management) Rules, 2017.
Answer as per the official UPSC answer key.
Which of the following are nitrogen-fixing plants ?
- 1. Alfalfa
- 2. Amaranth
- 3. Chickpea
- 4. Clover
- 5. Purslane (Kulfa)
- 6. Spinach
Select the correct answer using the code given below:
Answer (a) & explanation
Alfalfa, chickpea and clover fix nitrogen (a). Nitrogen fixing is done by Rhizobium bacteria living in the root nodules of legumes, which turn nitrogen from the air into forms plants can use. Item 1 is right: alfalfa (lucerne) is a legume fodder crop. Item 3 is right: chickpea (gram) is a legume. Item 4 is right: clover is a legume. Items 2, 5 and 6 are wrong: amaranth, purslane (kulfa) and spinach are leafy plants of other families and fix no nitrogen.
Notice why farmers grow legumes in crop rotation: they enrich the soil and cut the need for urea. Nitrogen is also fixed by free-living microbes such as Azotobacter and cyanobacteria, used as biofertilisers in paddy fields.
Answer as per the official UPSC answer key.
The “Miyawaki method” is well known for the :
Answer (c) & explanation
The Miyawaki method creates mini forests in urban areas (c). Developed by the Japanese botanist Akira Miyawaki in the 1970s, the method plants many native species, about three to five saplings per square metre, very close together on small plots, in layers from shrubs to tall trees. The saplings compete for light and grow about ten times faster, so a dense mini forest forms in two to three years, which suits cities. Option (a) is wrong: it is not about commercial farming. Option (b) is wrong: it uses native, not GM, plants. Option (d) is wrong: it has nothing to do with wind energy.
Notice its use in Indian cities such as Chennai, Bengaluru and Hyderabad. Critics say such small plots cannot replace natural forests.
Answer as per the official UPSC answer key.
Biodiversity and species 5
With reference to “Gucchi” sometimes mentioned in the news, consider the following statements :
- 1. It is a fungus.
- 2. It grows in some Himalayan forest areas.
- 3. It is commercially cultivated in the Himalayan foothills of north-eastern India.
Which of the statements given above is/are correct ?
Answer (c) & explanation
Statements 1 and 2 are correct (c). Statement 1 is right: gucchi is the morel mushroom, a fungus with a honeycomb-like cap. Statement 2 is right: it grows wild in the Himalayan forests of Jammu and Kashmir, Himachal Pradesh and Uttarakhand, usually in spring after snowmelt. Statement 3 is wrong: it is gathered from the wild, not commercially farmed in the north-eastern foothills. That scarcity is why it sells for ₹20,000–30,000 a kilogram or more.
Notice other high-value Himalayan forest products: keeda jadi (Cordyceps, the caterpillar fungus) and kutki. Notice too the GI tag culture: J&K's saffron and Himachal's Kala Zeera. Morels are part of the minor forest produce that supports hill communities.
Answer as per the official UPSC answer key.
Which of the following is not a bird ?
Answer (a) & explanation
The golden mahseer is not a bird (a). The golden mahseer (Tor putitora) is a large freshwater fish of fast-flowing Himalayan rivers, called the "tiger of the water" by anglers. It is listed as Endangered on the IUCN Red List, hit by dams, sand mining and overfishing. The Indian nightjar (b) is a night bird known for its call. The spoonbill (c) is a wading bird with a flat, spoon-shaped bill. The white ibis (d) is a wading bird with a long, curved bill.
Notice that the golden mahseer is the state fish of Uttarakhand, Himachal Pradesh and J&K. UPSC often mixes fish into bird lists. Spoonbills and ibises gather at Bharatpur (Keoladeo National Park).
Answer as per the official UPSC answer key.
“Biorock technology” is talked about in which one of the following situations ?
Answer (a) & explanation
Biorock is used to restore damaged coral reefs (a). Biorock, or mineral accretion, passes a weak, safe electric current through a steel frame placed under the sea. Minerals dissolved in sea water, mainly calcium carbonate, build up on the frame like limestone. Coral pieces fixed to it grow fast and resist stress better. Option (b) describes bio-based building materials. Option (c) describes shale gas survey. Option (d) describes salt licks for wildlife.
Notice that India's Zoological Survey of India, with the Gujarat Forest Department, tried biorock in the Gulf of Kachchh in 2017. Coral reefs face bleaching from warming seas; the world saw its fourth global bleaching event in 2023–24.
Answer as per the official UPSC answer key.
Certain species of which one of the following organisms are well known as cultivators of fungi ?
Answer (a) & explanation
Ants are well-known fungus farmers (a). Leafcutter ants of Central and South America cut pieces of leaves and carry them home. They do not eat the leaves; they use them to grow a fungus in underground gardens, and the fungus is their food. They even weed the garden and use bacteria that make antifungal chemicals to protect it. This is one of nature's oldest forms of agriculture, about 50 million years old. Cockroaches (b), crabs (c) and spiders (d) do not farm fungi.
Notice that some termites and ambrosia beetles also farm fungi, but neither is offered here. UPSC likes such symbiosis facts, like the fig and fig wasp, lichens (fungus plus alga) and mycorrhiza (fungus plus plant roots).
Answer as per the official UPSC answer key.
Consider the following statements :
DNA Barcoding can be a tool to:
- 1. assess the age of a plant or animal.
- 2. distinguish among species that look alike.
- 3. identify undesirable animal or plant materials in processed foods.
Which of the statements given above is/are correct ?
Answer (d) & explanation
Statements 2 and 3 are correct (d). DNA barcoding reads a short, standard stretch of a gene that differs between species, much like a barcode at a shop. In animals this is usually the COI gene of mitochondria. Statement 2 is right: it can tell apart look-alike species, such as cryptic insects or fish fillets. Statement 3 is right: it can find hidden or undesirable plant or animal material in processed foods, such as pork in a "beef" product, or adulteration in herbal medicines. Statement 1 is wrong: the barcode tells you which species something is, not its age.
Notice its use in wildlife crime: barcoding helps identify seized animal parts, such as pangolin scales, and protects food safety and trade.
Answer as per the official UPSC answer key.
Protected areas and conservation 2
Consider the following pairs :
| Wetland / Lake | Location
| 1. Hokera Wetland | Punjab
| 2. Renuka Wetland | Himachal Pradesh
| 3. Rudrasagar Lake | Tripura
| 4. Sasthamkotta Lake | Tamil Nadu
How many pairs given above are correctly matched ?
Answer (b) & explanation
Only two pairs are correct (b). All four are Ramsar sites. Pair 2 is right: Renuka wetland is in Sirmaur, Himachal Pradesh, named after the mother of Parashurama. Pair 3 is right: Rudrasagar lake is in Tripura, home to the Neermahal water palace. Pair 1 is wrong: Hokera wetland is near Srinagar in Jammu and Kashmir, not Punjab. Pair 4 is wrong: Sasthamkotta, the largest freshwater lake in Kerala, is in Kollam, not Tamil Nadu.
Notice that India has rapidly added Ramsar sites, reaching over 90 by 2025; Tamil Nadu has the most. The Ramsar Convention was signed in Iran in 1971, and World Wetlands Day is on 2 February. Chilika was India's first site (1981).
Punjab has several Ramsar sites (Harike, Kanjli), so a Punjab label looks safe.
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Answer as per the official UPSC answer key.
With reference to Indian laws about wildlife protection, consider the following statements :
- 1. Wild animals are the sole property of the government.
- 2. When a wild animal is declared protected, such animal is entitled for equal protection whether it is found in protected areas or outside.
- 3. Apprehension of a protected wild animal becoming a danger to human life is sufficient ground for its capture or killing.
Which of the statements given above is/are correct ?
Answer (b) & explanation
Only statement 2 is correct (b). Statement 2 is right: once a species is listed under the Wild Life (Protection) Act, 1972, it is protected everywhere, inside or outside a national park or sanctuary. Statement 1 is wrong: Section 39 makes certain wild animals, such as those hunted or found dead, government property, but not every wild animal in every case, so "sole property" is too wide. Statement 3 is wrong: only the Chief Wildlife Warden can allow a protected animal to be captured or killed, and only when it has become dangerous to human life; mere fear is not enough.
Notice the 2022 amendment, which cut the schedules to four and brought CITES listings into Indian law. Man-animal conflict cases test this rule often.
"sole property" is the over-strong word.
Answer as per the official UPSC answer key.
Climate change and international conventions 3
Among the following crops, which one is the most important anthropogenic source of both methane and nitrous oxide ?
Answer (b) & explanation
Rice is the major source of both gases (b). Flooded paddy fields have no oxygen in the soil, so microbes called methanogens break down organic matter and release methane. The nitrogen fertiliser used on rice adds nitrous oxide, especially when fields are drained and flooded in turns. No other crop does both on that scale. Cotton (a), sugarcane (c) and wheat (d) give off nitrous oxide from fertilisers, but are not grown in flooded fields, so they release little methane.
Notice other farm methane sources: enteric fermentation in cattle, the largest, and manure. India's answers include alternate wetting and drying and Direct Seeded Rice. Nitrous oxide is about 270 times stronger than CO₂ as a warming gas.
Answer as per the official UPSC answer key.
“Climate Action Tracker” which monitors the emission reduction pledges of different countries is a:
Answer (a) & explanation
It is a database created by research organisations (a). The Climate Action Tracker is run by two independent research groups, Climate Analytics and the NewClimate Institute. It rates each country's pledges (NDCs), targets and policies against the Paris Agreement goal of keeping warming to 1.5 °C, using grades from "critically insufficient" to "1.5 °C compatible". Option (b) is wrong: it is not part of the IPCC. Option (c) is wrong: it is not a UNFCCC committee. Option (d) is wrong: it is not run or funded by UNEP and the World Bank.
Notice the official tools: NDCs submitted every five years, and the Global Stocktake, the first of which ended at COP28 (Dubai, 2023). India's updated NDC targets net zero by 2070.
Answer as per the official UPSC answer key.
Consider the following statements :
- 1. “The Climate Group” is an international non-profit organization that drives climate action by building large networks and runs them.
- 2. The International Energy Agency in partnership with the Climate Group launched a global initiative “EP100”.
- 3. EP100 brings together leading companies committed to driving innovation in energy efficiency and increasing competitiveness while delivering on emission reduction goals.
- 4. Some Indian companies are members of EP100.
- 5. The International Energy Agency is the Secretariat to the “Under2 Coalition”.
Which of the statements given above are correct ?
Answer (b) & explanation
Statements 1, 3 and 4 are correct (b). Statement 1 is right: The Climate Group is an international non-profit that builds and runs large networks for climate action, such as RE100 for renewable power. Statement 3 is right: EP100 gathers companies that pledge to use energy more efficiently, gaining competitiveness while cutting emissions. Statement 4 is right: Indian firms such as Mahindra are members. Statement 2 is wrong: EP100 was launched with the Alliance to Save Energy, not the IEA. Statement 5 is wrong: The Climate Group itself is the secretariat of the Under2 Coalition of state and regional governments.
Notice EV100 for electric vehicles, another Climate Group network. India's own efficiency agency is the Bureau of Energy Efficiency (2002).
Answer as per the official UPSC answer key.
Pollution, environmental laws and green technology 5
In the context of WHO Air Quality Guidelines, consider the following statements :
- 1. The 24-hour mean of PM2·5 should not exceed 15 µg/m3 and annual mean of PM2·5 should not exceed 5 µg/m3.
- 2. In a year, the highest levels of ozone pollution occur during the periods of inclement weather.
- 3. PM10 can penetrate the lung barrier and enter the bloodstream.
- 4. Excessive ozone in the air can trigger asthma.
Which of the statements given above are correct ?
Answer (b) & explanation
Statements 1 and 4 are correct (b). Statement 1 is right: the 2021 WHO Air Quality Guidelines set PM2.5 at 15 µg/m³ for the 24-hour mean and 5 µg/m³ for the annual mean. Statement 2 is wrong: ground-level ozone forms when sunlight acts on pollutants, so it peaks in hot, sunny weather, not in bad weather. Statement 3 is wrong: PM2.5, not PM10, is fine enough to pass the lung barrier into the bloodstream. Statement 4 is right: excess ozone irritates airways and can trigger asthma.
Notice that India's National Ambient Air Quality Standards (2009) are much looser: PM2.5 at 60 (24-hour) and 40 (annual). The National Clean Air Programme (2019) targets cuts in 131 cities.
PM10 reaches the lungs, but the bloodstream needs the finer PM2.5.
Answer as per the official UPSC answer key.
With reference to polyethylene terephthalate, the use of which is so widespread in our daily lives, consider the following statements :
- 1. Its fibres can be blended with wool and cotton fibres to reinforce their properties.
- 2. Containers made of it can be used to store any alcoholic beverage.
- 3. Bottles made of it can be recycled into other products.
- 4. Articles made of it can be easily disposed of by incineration without causing greenhouse gas emissions.
Which of the statements given above are correct ?
Answer (a) & explanation
Statements 1 and 3 are correct (a). Polyethylene terephthalate (PET) is the plastic of water and soft-drink bottles. Statement 1 is right: as a fibre it is polyester, often blended with cotton and wool to add strength and resist creasing. Statement 3 is right: PET bottles are widely recycled into fibre, carpets and new bottles. Statement 2 is wrong: it is not suited to storing every alcoholic drink; long storage of strong spirits can draw out chemicals. Statement 4 is wrong: burning PET releases CO₂ and other pollutants.
Notice that India recycles a high share of its PET bottles, much of it into polyester fibre. The Plastic Waste Management Rules (amended 2022) ban many single-use plastics and set EPR targets for producers.
Answer as per the official UPSC answer key.
Which one of the following has been constituted under the Environment (Protection) Act, 1986 ?
Answer (c) & explanation
The Central Ground Water Authority was set up under the Environment (Protection) Act (c). The Central Ground Water Authority came in 1997 under Section 3(3) of the Environment (Protection) Act, 1986, after a Supreme Court order, to regulate and control groundwater use. It issues No Objection Certificates for drawing groundwater and notifies over-exploited areas. Option (a) is wrong: the Central Water Commission dates from 1945 and is an attached office under the Jal Shakti Ministry. Option (b) is wrong: the Central Ground Water Board is a survey and research body. Option (d) is wrong: the National Water Development Agency (1982) is a society that plans river linking.
Notice that India is the world's largest user of groundwater, which is why the Atal Bhujal Yojana targets falling water tables.
CGWB and CGWA sound alike. The Board studies groundwater; the Authority regulates it.
Answer as per the official UPSC answer key.
Consider the following statements :
- 1. Other than those made by humans, nanoparticles do not exist in nature.
- 2. Nanoparticles of some metallic oxides are used in the manufacture of some cosmetics.
- 3. Nanoparticles of some commercial products which enter the environment are unsafe for humans.
Which of the statements given above is/are correct ?
Answer (d) & explanation
Statements 2 and 3 are correct (d). Statement 2 is right: nanoparticles of zinc oxide and titanium dioxide are used in sunscreens, creams and other cosmetics, because they block UV rays without leaving a white layer. Statement 3 is right: some engineered nanoparticles that enter the air, water or soil can be unsafe: their tiny size lets them reach deep into the lungs, cross cell walls and harm tissues. Statement 1 is wrong: nanoparticles occur in nature, in volcanic ash, sea spray, desert dust and smoke from forest fires.
Notice the scale: a nanometre is a billionth of a metre, and nanoparticles are 1–100 nm across. At that size materials behave differently: gold looks red, and silver nanoparticles kill microbes.
Answer as per the official UPSC answer key.
Consider the following :
- 1. Carbon monoxide
- 2. Nitrogen oxide
- 3. Ozone
- 4. Sulphur dioxide
Excess of which of the above in the environment is/are cause(s) of acid rain ?
Answer (b) & explanation
Nitrogen oxides and sulphur dioxide cause acid rain (b). Sulphur dioxide (SO₂), mostly from burning coal and oil, and nitrogen oxides (NOₓ), mostly from vehicles and power plants, react with water in the air to form sulphuric and nitric acids. These fall as acid rain, with a pH below about 5.6. Item 1 is wrong: carbon monoxide is a poisonous gas but does not make rain acidic. Item 3 is wrong: ozone at ground level is a harmful smog pollutant, but it is not an acid-forming gas. So options (a), (c) and (d) fall.
Notice the famous Indian case: the yellowing of the Taj Mahal was blamed partly on SO₂ from the Mathura refinery, which led to the Taj Trapezium Zone.
Answer as per the official UPSC answer key.
All years by topic
Every question from 2011 to 2026, grouped by syllabus topic, with year-wise trends.