Environment & Ecology: syllabus hub.
Syllabus: UPSC Pre GS1: Environmental Ecology, Biodiversity & Climate Change; Mains GS3
Questions per year and the most repeated subtopics.
Renewable energy for UPSC: solar, wind, hydro and bioenergy potential, the 500 GW target, PM-KUSUM, PM Surya Ghar, solar parks, storage, grid…
Paris Agreement for UPSC: 1.5 and 2 degree goals, NDCs, Article 6 markets, global stocktake, finance goal, India's updated NDC and Panchamrit,…
Montreal Protocol for UPSC: how the ozone hole formed, Vienna Convention, phase-out schedules, Kigali Amendment on HFCs, India Cooling Action Plan and…
Green hydrogen for UPSC: grey, blue and green hydrogen, electrolysers, National Green Hydrogen Mission and SIGHT, India's standard, uses, costs and PYQs.
CITES for UPSC: origin, Appendices I, II and III, permits, CoPs, India's Wildlife Protection Act 2022 changes, WCCB, TRAFFIC and wildlife trade…
Western Ghats for UPSC: six States, formation, passes, rivers, endemic species, UNESCO and hotspot status, Gadgil vs Kasturirangan reports and landslides.
Attempt them here.
Which of the following statements with regard to Green Hydrogen is/are correct ?
Select the answer using the code given below :
Statements 2 and 3 are correct (b). Statement 2 is right: green hydrogen comes from splitting water by electrolysis, using renewable power. Statement 3 is right: the National Green Hydrogen Mission (2023) targets 5 MMT of green hydrogen a year by 2030 and about 50 MMT of avoided CO₂-equivalent emissions each year. Statement 1 is wrong: hydrogen from natural gas with carbon capture is blue hydrogen. So options (a), (c) and (d) fail.
Notice the colours: grey hydrogen from gas without capture (most hydrogen today), brown from coal, and pink from nuclear power. The mission's SIGHT programme supports electrolyser making. Uses include fertilisers, refineries, steel and shipping fuel.
1 says "decarbonized", which sounds green. Gas with CCS is blue.
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Answer as per the official UPSC answer key.
Which of the following statements in relation to NIRANTAR (National Institute for Research and Application of Natural Resources to Transform, Adapt and Build Resilience), a platform of institutions under the Ministry of Environment, Forest and Climate Change, is/are correct ?
Select the answer using the code given below :
Statements 1 and 3 are correct (b). NIRANTAR groups the Environment Ministry's institutes into verticals. Statement 1 is right: Ecosystem Survey and Analysis is led by the Botanical Survey of India, Kolkata, with bodies like the FSI and ZSI. Statement 3 is right: Capacity Development Support is led by the Indian Institute of Forest Management, Bhopal. Statement 2 is wrong: Research and Management of Ecosystem Service is led by ICFRE, Dehradun; the Central Zoo Authority is only a member. So options (a), (c) and (d) fail.
Notice the purpose: pooling institutes avoids duplicate work and links research to climate adaptation and resilience. Other Ministry bodies include the Wildlife Institute of India (Dehradun) and GBPNIHE for the Himalaya.
the Central Zoo Authority does sit in that vertical, but as a member, not the lead.
Answer as per the official UPSC answer key.
Consider the following statements with reference to India’s response to climate change :
Which of the following relationships among the above statements is/are correct ?
Select the answer using the code given below :
Relationships 1 and 2 are correct (b). Relationship 1 is right: the LT-LEDS (2022) lays out India's path to net zero by 2070, and BUR-4 reported a fall of about 7.9% in 2020 emissions over 2019, real data in line with that path. Relationship 2 is right: Statement III wants quick, short-term cuts, while the LT-LEDS is a long, gradual plan, so III contradicts I. Relationship 3 is wrong: two contradicting statements cannot together set a premise. So options (a), (c) and (d) fail.
Notice the cause of the 2020 fall: the COVID-19 lockdowns, not a lasting trend. India's updated NDC (2022) targets cutting emissions intensity of GDP by 45% from 2005 levels by 2030. Biennial Transparency Reports now replace BURs.
"together establish" sounds positive, but two statements that clash cannot form one premise.
Answer as per the official UPSC answer key.
With respect to the Western Hoolock Gibbons, which of the following statements is/are correct ?
Select the answer using the code given below :
Statements 1 and 2 are correct (b). Statement 1 is right: India's only ape, the western hoolock gibbon, is Endangered on the IUCN Red List and gives its name to the Hollongapar Gibbon Sanctuary in Assam. Statement 2 is right: gibbons move by brachiation, swinging arm over arm through the canopy. Statement 3 is wrong: they are "lesser apes", slim and light, about 6–9 kg, nothing like a heavy gorilla. So options (a), (c) and (d) fail.
Notice their habits: they live in pairs with their young and sing loud duets at dawn. They are found south of the Brahmaputra in the North-East. Rail lines cutting through Hollongapar have raised concern, and canopy bridges were proposed to help them cross.
Answer as per the official UPSC answer key.
Which of the following best explain(s) the rationale for protecting mangrove ecosystems in the context of climate resilience ?
Select the answer using the code given below :
Only statement 3 explains the rationale (d). Statement 3 is right: by withstanding tidal surges and cyclones, mangroves act as natural bio-shields, and they offer biomass, such as fish, crabs, honey and fuel, for coastal villages. Statement 1 is wrong: mangroves do not store fresh water for paddy. Statement 2 is wrong: they are salt-tolerant, not salt-sensitive. Clearing them for farms or aquaculture ponds is exactly what harms them. So options (a), (b) and (c) fail.
Notice the proof: mangroves cut deaths in the 1999 Odisha super-cyclone and the 2004 tsunami. They also store much blue carbon. India's largest mangrove forest is the Sundarbans; the MISHTI scheme (2023) aims to plant more along the coast.
statement 2 says "salt-sensitive". Mangroves live in salt water because they tolerate it.
Answer as per the official UPSC answer key.
Which of the following statements with regard to the arrival of Amur Falcons at Doyang Lake in Nagaland each year from Mongolia is/are correct ?
Select the answer using the code given below :
Only statement 1 is correct (a). Statement 1 is right: around 2012, villages near Doyang in Nagaland, once known for mass hunting of the birds, turned into protectors, so the falcons now roost safely. Statement 2 is wrong: satellite tags only track the birds; they do not guide them. Statement 3 is wrong: Amur falcons stay only a few weeks, so they are not permanent residents. So options (b), (c) and (d) fail.
Notice their journey: they breed in Mongolia, Siberia and northern China, rest in Nagaland, then cross the Arabian Sea to winter in southern Africa, one of the longest raptor migrations. Pangti village is called the "Falcon Capital of the World". Tagged birds have been named after these villages.
Answer as per the official UPSC answer key.
With reference to Madhav National Park, which of the following statements is/are correct ?
Select the answer using the code given below :
Statements 1 and 2 are correct (b). Statement 1 is right: Madhav National Park in Shivpuri district became India's 58th tiger reserve in March 2025. Statement 2 is right: Sakhya Sagar lake inside it was named a Ramsar site in 2022. Statement 3 is wrong: the park lies wholly in Madhya Pradesh, not shared with Rajasthan. So options (a), (c) and (d) fail.
Notice MP's place as the "Tiger State", with the most tigers and nine reserves, including Kanha, Bandhavgarh, Pench and Panna. The NTCA approves tiger reserves under the Wild Life (Protection) Act. Kuno, also in MP, is home to India's reintroduced cheetahs. India has about 75% of the world's wild tigers.
Shivpuri is near the Rajasthan border, which makes "shared" sound believable.
Answer as per the official UPSC answer key.
Consider the following statements about Rhynchostylis retusa (Foxtail orchid) :
Which of the statements given above is/are correct ?
Statements 1 and 3 are correct (b). Statement 1 is right: the foxtail orchid grows on tree trunks and branches, using the tree only for support, so it is epiphytic, not a parasite. Statement 3 is right: it is the State flower of Arunachal Pradesh and of Assam, where it is the kopou phool, worn in Bihu dances. Statement 2 is wrong: it is not endemic; it grows across South and South-East Asia. So options (a), (c) and (d) fail.
Notice the North-East's orchid wealth: Arunachal alone has over 600 orchid species, and Sikkim's state flower, the Noble Dendrobium, is also an orchid. The Tipi Orchid Research Centre is in Arunachal. All wild orchids trade under CITES Appendix II.
it is famous in the North-east, but "endemic" means found nowhere else.
Answer as per the official UPSC answer key.
UNEP’s Emissions Gap Report 2026, ‘The Point of Return’, released on 21 October 2026, says warming will now exceed 1.5°C. Current policies point to 2.8°C, and even full delivery of national pledges gives 2.6°C. But if emissions fall 18% by 2030, 45% by 2035 and 69% by 2040 from 2025 levels, warming could peak at 1.7–1.8°C and return to 1.5°C by 2100, with about a 50% chance.
UPSC angle: Prelims: UNEP, EGR, Paris Agreement articles, Global Stocktake. · Mains GS-III: overshoot, equity, India’s NDC.
22 Oct 2026
India is set to make 1% blending of Sustainable Aviation Fuel (SAF) compulsory for international flights from 2027, rising to 2% in 2028 and 5% in 2030, industry sources told The Hindu. The trigger is ICAO’s CORSIA, whose mandatory phase begins in January 2027. Indian airlines may need about 5 million tonnes of carbon credits a year, costing $50–75 million, while a full national SAF policy is still awaited.
UPSC angle: Prelims: ICAO, CORSIA, SAF pathways, Panipat. · Mains GS-III: decarbonising aviation; biofuels.
22 Oct 2026
Opening the 7th Agrivoltaics World Conference at Bharat Mandapam on 21 October 2026, the first in the Global South, Renewable Energy Minister Pralhad Joshi said the next phase of PM-KUSUM will carry one of the world’s most ambitious agrivoltaics programmes. Agriculture Minister Shivraj Singh Chouhan said the policy must work for the 85% of farmers who are small and marginal, with an average holding of just 0.96 hectare.
UPSC angle: Prelims: PM-KUSUM, TERI estimate, capacity numbers. · Mains GS-III: land-energy-food nexus.
22 Oct 2026
With Delhi’s AQI at 244 (‘Poor’) on 21 October 2026, the Commission for Air Quality Management (CAQM) invoked all 25 actions of Stage I of the Graded Response Action Plan (GRAP) across the NCR. The focus is on dust control at construction sites, covered transport of debris, anti-smog guns, water sprinkling, no open burning and strict PUC checks. AQI had been 179 (‘Moderate’) a day earlier.
UPSC angle: Prelims: GRAP stages, AQI bands, CAQM, NCAP. · Mains GS-III: air quality governance.
22 Oct 2026
MNRE Secretary Santosh Kumar Sarangi said on 19 October 2026 that the Centre is planning a central sector scheme to help States adopt agrivoltaics, either standalone or within PM-KUSUM 2.0. He expects capacity to cross 5 GW in three to four years if States notify feed-in tariffs. India hosts the 7th Agrivoltaics World Conference in New Delhi from 21 to 23 October.
UPSC angle: Prelims: agrivoltaics, PM-KUSUM components, feed-in tariffs. · Mains GS-III: energy transition and food security.
20 Oct 2026
India has begun a national Red List assessment of its 1,211 regularly occurring bird species using the IUCN framework. By 19 October 2026, a preliminary review of 107 species was complete, with the Great Indian Bustard proposed as Critically Endangered and the Indian Roller as Vulnerable. A final assessment is expected towards the end of 2027.
UPSC angle: Prelims: IUCN categories, species and their proposed status, lead institutions. · Mains GS-III: biodiversity conservation and data gaps.
20 Oct 2026