UPSC Prelims 2026 Revision Checklist: Top 30 Environment topics aspirants shouldn’t miss

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Here’s a checklist of important environment topics, conventions, climate developments, and conservation issues you shouldn’t miss. Are they part of your Prelims revision plan yet?

#1 Atlantic Meridional Overturning Circulation (AMOC)

— AMOC stands for Atlantic Meridional Overturning Circulation. The AMOC circulates water from north to south and back in a long cycle within the Atlantic Ocean. This circulation brings warmth to various parts of the globe and also carries nutrients necessary to sustain ocean life.

— The circulation process begins when warm water near the surface flows to the poles (such as the Gulf Stream in the North Atlantic), where it cools and develops sea ice. As this ice forms, salt remains in the ocean water. Because of the high salt content, the water becomes denser, sinks, and travels southward in the depths below. Eventually, the water is drawn back up to the surface and warms up in a process known as upwelling, completing the cycle.

#2 Ramsar sites

— Ramsar sites are wetlands, recognized globally on the List of Wetlands of International Importance. Under the Ramsar Convention, an international treaty established in 1971, the primary goal of the sites is to promote the conservation and responsible use of wetlands across the globe.

— India became a party to the ‘Convention on Wetlands’, also known as the Ramsar Convention on 1st February 1982. Presently, India stands first in South Asia and third in Asia in terms of number of designated sites.

— In India, the Sundarban Wetland is the largest Ramsar site in terms of area.

Note: Read about the latest induction of Ramsar Sites in India

#3 World Earth Day

— Earth Day, which focuses on raising awareness about environmental issues such as climate change, pollution, deforestation, and biodiversity loss, is observed every year on April 22.

— This year’s theme was  “Our Power, Our Planet”. This theme emphasises leveraging community action, accelerating the transition to renewable energy, and boosting accountability for environmental damage to tackle the climate crisis. It highlights that collective, daily action from individuals is essential to achieving a sustainable future.

— Earth Day was first celebrated on April 22, 1970, marking the beginning of the modern environmental movement. It was initiated by Gaylord Nelson, a U.S. senator who wanted to raise awareness about pollution and environmental damage after witnessing the impact of a massive oil spill.

#4 Census of Water Bodies

— The Second Census of Water Bodies, conducted by the Ministry of Jal Shakti with the reference year 2023-24 (conducted 2024-25), is being carried out in conjunction with the 7th Minor Irrigation Census to create a national database of water bodies. This census includes ponds, tanks, lakes, reservoirs, and for the first time, springs, to assess their usage, condition, and encroachment status.

— The first Water Bodies Census, which was conducted in 2018-19 did not include free-flowing water systems, temporary constructions, and private/industrial tanks that are not intended for public storage. It specifically excluded the ocean, rivers, streams, waterfalls, canals, swimming pools, private home tanks, and temporary excavation pits.

#5 India submits first Nagoya Protocol Report

— Recently, India has submitted the First National Report (NR1) on the implementation of the Nagoya Protocol on access and benefit sharing (ABS).  

— According to the report, India implements the Access and Benefit-Sharing mechanism through a three-tier institutional framework comprising the NBA, State Biodiversity Boards (SBBs) or Union Territory Biodiversity Councils (UTBCs) at the sub-national level; and the Biodiversity Management Committees (BMCs) at the local level, constituted by elected local bodies. This decentralised system has enabled coordinated action at national, state, and local levels.

#6 India’s CO2 emissions and its climate targets for 2035

— India’s carbon dioxide emissions grew by just 0.7 per cent in the year 2025, the slowest growth in more than two decades, a new analysis has found. Emissions from the power sector, which accounts for almost half of India’s CO2 emissions, fell by about 3.8 per cent in 2025, and could have been the major contributor to the slowdown in overall emissions for the year.

— Carbon dioxide accounts for nearly 80 per cent of India’s total greenhouse gas emissions. A slowdown in the growth rate of India’s emissions is a global good news from the environmental perspective since the country is the third largest emitter of greenhouse gases.

— India said it would ensure that at least 60% of its electricity installed capacity in 2035 was based on non-fossil fuel sources, up from the 50% target it had set for 2030.

— It has promised to attain at least a 47% reduction in emissions intensity, or emissions per unit of GDP, on 2005 levels, which is two percentage points more than its current target of 45% for 2030. And, it has promised to create a carbon sink that is at least 3.5 to 4 billion tonnes of CO2-equivalent larger than what existed in 2005.

#7 Minamata Convention on Mercury (COP-6)

— The sixth meeting of the Conference of the Parties to the Minamata Convention on Mercury (COP-6), held in Geneva from 3 to 7 November 2025, brought together over 1,000 participants in person and nearly 4,000 online viewers.

— COP-6 adopted new amendments to Annex A, establishing a global phase-out of dental amalgam by 2034, a decision described by many delegations as a historic milestone for the Convention. Parties strengthened action on artisanal and small-scale gold mining (ASGM), recognizing the importance of providing alternative livelihoods for mining communities, particularly those in vulnerable situations, when moving away from mercury use.

#8 Microalgae-based air tower

— New Delhi has commissioned India’s first microalgae-based PureAir Tower™ along the Aerocity highway corridor, marking a new experiment in science-driven urban air mitigation. Installed on a busy central median.

— Unlike conventional smog towers that rely on mechanical filtration and periodic filter replacement, the PureAir Tower™ uses photosynthetic microalgae to absorb carbon dioxide (CO₂), particulate matter (PM), and nitrogen oxides (NOx) directly at street level. Through natural bioremediation, pollutants are converted into oxygen and algal biomass in real time, with minimal energy input and no secondary filter waste.

#9 Gases released from burning crude

— Burning crude releases a toxic cocktail of gases — sulphur dioxide, carbon monoxide, hydrogen sulfide, and nitrogen oxides. Not just these, dense clouds of soot, packed with partially burned hydrocarbons and heavy metals are also released, which significantly spike the pollution in a particular region.

— These plumes don’t just rise harmlessly into the upper atmosphere; they spread at ground level, embedding themselves in soil, water… and human lungs.

#10 Convention on the Conservation of Migratory Species of Wild Animals (CMS)

— The 15th Meeting of the Conference of the Parties (COP15) to the Convention on the Conservation of Migratory Species of Wild Animals (CMS) was held at the Bosque Expo in Campo Grande, Mato Grosso do Sul, Brazil.

— This is the first time CMS COP is hosted in Brazil. CMS COP15 was convened under the slogan “Connecting Nature to Sustain Life”. The Convention on Migratory Species of Wild Animals, also known as the Bonn Convention, was adopted on 23 June 1979.

What is CMS?

— The CMS is a framework convention and encompasses a range of agreements, memoranda of understanding, and special species initiatives. As an environmental treaty under the aegis of the United Nations Environment Programme, CMS provides a global platform for the conservation and sustainable use of migratory animals and their habitats.

#11 Expert Appraisal Committee

— An Environment Ministry expert panel has recommended clearance for construction of NHPC’s 1,720 MW Kamala hydroelectric project in Arunachal Pradesh which entails felling of 23.4 lakh trees.

— The Expert Appraisal Committee (EAC) is a multi-disciplinary sectoral appraisal committee composed of various subject matter experts for screening, scoping and appraisal of Projects / Activities specified under the EIA Notification, 2006, as amended.

#12 Rat-hole mining

— Rat-hole mining is a method of extracting coal from narrow, horizontal seams, prevalent in Meghalaya. The term “rat hole” refers to the narrow pits dug into the ground, typically just large enough for one person to descend and extract coal.

#13 Higher ocean temperatures

— Higher ocean temperatures can have irreversible consequences for marine ecosystems. For instance, warmer oceans lead to an increase in ocean stratification — the natural separation of an ocean’s water into horizontal layers by density, with warmer, lighter, less salty, and nutrient-poor water layering on top of heavier, colder, saltier, nutrient-rich water. Usually, ocean ecosystems, currents, wind, and tides mix these layers.

— The rise in temperatures, however, has made it harder for the water layers to mix with each other. Due to this, oceans are able to absorb less carbon dioxide from the atmosphere, and the oxygen absorbed is not able to mix properly with cooler ocean waters below, threatening the survival of marine life.

— Warmer oceans cause marine heat waves (MHWs), which occur when the surface temperature of a particular region of the sea rises to 3 or 4 degrees Celsius above the average temperature for at least five days. Between 1982 and 2016, such heatwaves have doubled in frequency and have become longer and more intense, according to a 2021 study by the UN’s Intergovernmental Panel on Climate Change (IPCC).

— According to several studies, higher ocean temperatures may also result in more frequent and more intense storms like hurricanes and cyclones. Warmer temperatures lead to a higher rate of evaporation as well as the transfer of heat from the oceans to the air. That’s why, when storms travel across hot oceans, they gather more water vapour and heat. This results in more powerful winds, heavier rainfall, and more flooding when storms reach the land — meaning heightened devastation for humans.

#14 Eco-Sensitive Zones (ESZ)

— The National Environment Policy (2006) defines Eco-Sensitive Zones as “areas/zones that possess unique environmental resources that require special attention for their conservation” because they contain landscape, wildlife, biodiversity, historical and natural values.

— There are no restrictions on agricultural and horticultural practices run by local communities, dairy farming, aquaculture, fisheries, poultry farms, goat farms, food-related units, etc. No new commercial construction is permitted within one kilometer of the boundary of a protected area or an eco-sensitive zone. However, there are no restrictions for local residents; they can build on their own land for their own use.

#15 Loss and Damage Fund

— The US has withdrawn from the board of the recently-created Loss and Damage Fund which is meant to provide financial support to countries ravaged by climate change disasters, Reuters news agency reported. 

— The Loss and Damage Fund was created at the COP27 climate meeting in Egypt in 2022 after several years of protracted negotiations. Developing countries, particularly small island states that face the greatest threats from climate impacts, had been demanding financial assistance in case of climate-related disasters, arguing that they were having to suffer due to a problem created by rich and developed countries. 

#16 Tropical Forest Forever Facility (TFFF)

— The TFFF is an investment fund designed as a permanent, self-financing vehicle through which net returns will be awarded to up to 74 developing tropical forest countries for keeping their existing old-growth forests intact.

— The fund will look to raise $25 billion from wealthy governments and philanthropists, and an additional $100 billion in private investment. Then, the amount will be invested into a mixed portfolio of investments, including public and corporate market bonds, with annual returns used as a reward to tropical forest nations for conserving their forests. Note that payments to countries will be based on satellite remote sensing data that track forest canopy cover annually in a low-cost and transparent manner.

— The TFFF is designed to change this and pay for the conservation of the world’s major tropical forests, which provide a range of ecosystem services, including carbon storage. Put simply, the fund will help landowners to conserve forests by ensuring that the value they bring as standing forests is more than from cutting them down.

#17 Forest Advisory Committee (FAC)

— The Forest Advisory Committee (FAC) is a statutory body under the Forest (Conservation) Act, 1980, which advises the government on matters related to the diversion of forest land for non-forest purposes like mining or industry.

— The Van Adhiniyam (formerly Forest Conservation Act, 1980) is considered to be violated when forest land is permitted for “de-reservation, non-forest use, lease, or clear felling” without prior approval of the Centre under the law.

— The FAC recommended penal compensatory afforestation in addition to penal provisions provided in the Van Adhiniyam Rules, 2023. Penal compensatory afforestation refers to restoration efforts which are ordered in addition to the legally mandated compensatory afforestation for non-forestry use of forest land for infrastructure projects, industries.

#18 Convention on International Trade in Endangered Species of Wild Fauna and Flora (CITES)

— The Convention on International Trade in Endangered Species of Wild Fauna and Flora (CITES) is a global treaty with 185 signatories. CITES is a legally binding international agreement between states that was adopted in 1973 and has been in existence since 1975.

— India became a party to CITES in 1976. Every member country designates their own CITES authorities.

— No international shipment of endangered species is allowed without export and import permits from the CITES authorities of the two countries involved. CITES allows regulated trade. Export and import of listed species (in its three Appendices) are only permitted with valid CITES licenses granted by the designated national authority.

#19 Meteorological Parameters under the Air Quality Index

— Air Quality indicators are monitored at about 3 m height from the ground with online sophisticated instruments. These instruments are operated round the clock, and data is recorded and stored at every 5-minute interval for quality check and further analysis.

— Pollutants monitored: PM1, PM2.5, PM10, Ozone, CO, NOx (NO, NO2), SO2, BC, Methane (CH4), Non-methane hydrocarbons (NMHC), VOC’s, Benzene, Mercury.

— Monitored Meteorological Parameters: UV Radiation, Rainfall, Temperature, Humidity, Wind speed, Wind direction, solar radiation.

#20 Common Effluent Treatment Plants (CETPs)

— The Union Environment Ministry has proposed to exempt common municipal solid waste management facilities and common effluent treatment plants (CETPs) from obtaining prior environmental clearance. At present, CETPs are not exempt from obtaining prior environmental clearance (EC). They require EC under the Environmental Impact Assessment (EIA) Notification, 2006, which was issued under the Environment (Protection) Act of 1986.

— A Common Effluent Treatment Plant (CETP) is a centralized facility that collects and treats wastewater from multiple industries, especially small and medium-sized enterprises (SMEs) within a cluster or industrial estate.

— Solid waste management facilities and CETPs are governed under provisions of the Water Act, 1974, and the Air Act, 1981, and the regulatory regimes under these statutes are both stringent and comprehensive.

#21 Effects of the oil spill on marine life

— Oil destroys the insulating ability of fur-bearing mammals, such as sea otters, and the water repellency of a bird’s feathers, thus exposing these creatures to the harsh elements. Without the ability to repel water and insulate from the cold water, birds and mammals will die from hypothermia.

— Dolphins and whales can inhale oil, which can affect lungs, immune function and reproduction. Many birds and animals also ingest oil when they try to clean themselves, which can poison them.

— Fish, shellfish, and corals may not be exposed immediately, but can come into contact with oil if it is mixed into the water column — shellfish can also be exposed in the intertidal zone. When exposed to oil, adult fish may experience reduced growth, enlarged livers, changes in heart and respiration rates, fin erosion, and reproduction impairment.

#22 Nature 2030 programme

— The Nature 2030 IUCN Programme, adopted by democratic vote at the IUCN World Conservation Congress in Marseille, lays out its goals for the first time over a decade. It is a call for action from our Members, Commissions, and Secretariat. This long-term vision is consistent with the United Nations’ 2030 Agenda for Sustainable Development and the post-2020 global biodiversity framework.

— The Programme identifies major areas of activity and establishes aspirational goals as well as success metrics. It will assist the Union in providing for people, land, water, oceans, and climate through five routes to transformative change: acknowledge, retain, restore, resource, and reconnect.

#23 Biodiversity Beyond National Jurisdictions (BBNJ)

— The High Seas Treaty, also known as the Biodiversity Beyond National Jurisdictions (BBNJ), because it deals with activities in international waters, seeks to curb pollution, and excessive resource extraction, while promoting efforts for sustainable use of biodiversity and other marine resources. One of the consequences of the new treaty would be the demarcation of protected areas in high seas, similar to national parks or wildlife reserves. High seas are regions beyond the territorial waters and the Exclusive Economic Zones (EEZs) of a nation.

— The treaty would serve as a legally binding international instrument under the UN Convention on the Law of the Sea (UNCLOS), which is a much broader agreement that extends to all oceans and defines the rights and duties of countries in their use of oceans and their resources.

— India has signed on to the BBNJ but has not yet ratified it. Enactment of a law is not necessary for ratification. India’s move to go in for legislation is aimed at preparing itself to make productive use of the new treaty. The treaty would place certain obligations on countries, for example, in conducting marine impact assessments ahead of undertaking any major project in the seas. Such activities would require institutional capabilities to be built. Making use of the economic benefit-sharing provisions would also need elaborate expertise.

#24 Green Climate Fund (GCF)

— The Green Climate Fund (GCF) is a fund for climate finance that was established within the framework of the United Nations Framework Convention on Climate Change (UNFCCC).

— It is considered the world’s largest fund of its kind. Its objective is to assist developing countries with climate change adaptation and mitigation activities.

#25 Atmospheric SO2

— The Environment Ministry exempted the majority of India’s coal-based thermal plants from installing systems that are designed to remove sulphur dioxide (SO2) emissions, a key contributor to air pollution. Once released into the atmosphere, SO2 usually reacts with ammonia (NH3) to produce ammonium sulfate, which is responsible for roughly one-third of India’s fine particulate matter (PM2.5) pollution, according to recent research by the Centre for Research on Energy and Clean Air (CREA).

— PM2.5 is injurious to human health as it can lead to chronic diseases such as asthma, heart attack, bronchitis, and other respiratory problems. Direct exposure to high levels of SO2 can irritate the eyes, throat, and lungs. Long-term exposure can result in increased risk of heart attacks, strokes, and premature death, according to CREA.

— SO2 also affects the environment as it contributes to the formation of acid rain, which can damage ecosystems.

#26 Biostimulants in agriculture

— Biostimulants are substances or microorganisms that stimulate natural processes in plants to enhance nutrient uptake, growth, yield, and stress tolerance.

— They do not supply nutrients directly like traditional fertilisers (e.g., NPK), but instead support plant physiology. Biostimulants are now covered under the Fertiliser Control Order 1985 bringing them under the same legal framework as fertilisers.

#27 Illegal sand mining

— Illegal sand mining causes environmental damage such as riverbed degradation, loss of aquatic habitat, increased turbidity, water table depletion, soil erosion, flooding, infrastructure damage, loss of fertile land, negative impact on local ecosystems, decreased water quality, and a risk to the ecological balance of the riverine regime.

— Coming down heavily on rampant illegal sand mining in the National Chambal Gharial Sanctuary, flagging its devastating impact on endangered wildlife, river ecology, and public safety, the Supreme Court in April, 2026 said state cannot plead helplessness and issued a series of stringent directions to curb the menace.

— The ruling underscores that environmental protection is integral to the right to life under Article 21 and signals a strong judicial push to tackle illegal mining networks that threaten ecology, governance, and human safety.

#28 Lion census 2025

— The most recent population assessment exercise in Gujarat found 891 lions, representing a 32% increase in population since 2020. Lions’ range has grown by 17% over the last five years, from 30,000 to 35,000 square kilometres, and they currently cover 58 talukas (up from 53 in 2020) throughout 11 districts.

Lion Census data.

— Asiatic lions have recovered dramatically from a population of less than 200 in the 1960s, when their last home in Gir was designated for special protection. For the most part, this progress has been long and steady—the population did not reach 300 until 1995, when the lion broke free from the shelter of the woodlands.

#29 COP30

The 30th edition of the Conference of the Parties to the UN Framework Convention on Climate Change (COP30), the annual two-week climate talks, concluded in Belem, Brazil on 22nd November. The Presidency has framed this year’s conference as the “implementation COP,”—was meant to focus less on what the world must do, rather on how to make it all happen.

Key takeaways from COP30:

#30 Marine protected area (MPA)

— A marine protected area (MPA) is essentially a zone in the ocean where human activities are more rigorously regulated than the surrounding waterways, akin to land-based parks.

1. Dugong Conservation Reserve – Tamil Nadu

2. Point Calimere Wildlife Sanctuary – Tamil Nadu

3. Gahirmatha – Odisha

4. Haliday Island – West Bengal

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