Pollution, Climate Change & International Environmental Cooperation

Organic waste — sewage, food-processing effluent, animal dung — is not poisonous in itself. It harms water because bacteria decomposing it consume dissolved oxygen, and fish and other aquatic life suffocate. So the key measures of water quality are all about oxygen.

The Central Pollution Control Board uses these indicators to classify river stretches by "designated best use". For outdoor bathing, for instance, its primary criteria include dissolved oxygen of at least 5 mg/L and BOD of not more than 3 mg/L, along with limits on faecal coliforms and pH. A river stretch that fails these figures is listed as a polluted stretch.

Noise is regulated by the Noise Pollution (Regulation and Control) Rules, 2000, framed under the Environment (Protection) Act. Limits are set in decibels on the A-weighted scale, dB(A), separately for day (6 a.m. to 10 p.m.) and night. A silence zone covers an area of not less than 100 metres around hospitals, educational institutions and courts.

• E-waste — discarded electronics contain lead, mercury, cadmium and brominated flame retardants, and are often dismantled informally by hand. The E-Waste (Management) Rules, 2022 (replacing the 2016 rules; India's first e-waste rules date from 2011) rest on Extended Producer Responsibility (EPR): producers must ensure that a set share of what they sell is collected and recycled, through registered recyclers.
• Plastic — under the Plastic Waste Management Rules, 2016 as amended, identified single-use plastic items were banned from 1 July 2022, and the minimum thickness of plastic carry bags was raised to 120 microns from 31 December 2022. EPR applies to plastic packaging too.
• Bio-medical waste — the 2016 rules require segregation at source by colour: yellow (anatomical and soiled waste, for incineration), red (contaminated recyclable plastics such as tubing and gloves), white translucent (sharps), and blue (glassware and metallic implants).
• Soil and land — soil is degraded by erosion, salinisation and waterlogging from over-irrigation, excess fertiliser and pesticide, and mining and industrial waste. Under the desertification convention India has committed to restore 26 million hectares of degraded land by 2030, a target announced when India hosted the convention's conference in 2019.

Most of the atmosphere's ozone lies in the stratosphere, roughly 15 to 35 km above the surface, where it absorbs most of the Sun's harmful UV-B radiation. Its total amount in a column of air is measured in Dobson Units (DU); an "ozone hole" is a region where the column falls below 220 DU. The hole appears over Antarctica in the southern spring (September–October): in the dark polar winter, polar stratospheric clouds form at extremely low temperatures, and on their surfaces chlorine from CFCs is converted into reactive forms; when sunlight returns, it destroys ozone rapidly. A single chlorine atom can destroy thousands of ozone molecules, and bromine (from halons and methyl bromide) is even more destructive per atom.

The Kigali Amendment gives different schedules to different groups. Developed countries began their reduction in 2019 and cut by 85% by 2036. Most developing countries, including China, freeze in 2024 and cut 80% by 2045. India, with a few others, freezes in 2028 and reduces by 85% by 2047, from a 2024–26 baseline. India ratified the amendment in 2021, and in 2019 it released the India Cooling Action Plan, among the first national plans to treat cooling demand — and therefore refrigerant gases — as a single policy problem.

Carbon dioxide in the air stood at about 280 parts per million (ppm) before industrialisation and has risen to more than 420 ppm in recent years, mainly from burning fossil fuels and clearing forests. The IPCC's Sixth Assessment Report (2021–2023) concluded that it is "unequivocal" that human influence has warmed the atmosphere, ocean and land, and that global surface temperature in 2011–2020 was about 1.1 °C above the 1850–1900 average. The gases differ in how strongly and how long they trap heat, which is captured by the Global Warming Potential (GWP) — the warming caused by a gas over a set period (usually 100 years) relative to the same mass of CO₂.

• Nitrogen trifluoride (NF₃) was added to the list for the Kyoto Protocol's second commitment period. Water vapour is the most abundant greenhouse gas, but it acts as a feedback — warmer air holds more of it — rather than as a gas humans emit directly to drive the change.
• Aerosols pull the other way: sulphate particles reflect sunlight and cool the planet, masking part of the warming. Black carbon (soot) is the exception — it absorbs sunlight and, settling on snow and ice, darkens them and speeds melting. It is a short-lived climate pollutant, not part of the Kyoto basket.
• Positive feedbacks amplify warming: melting ice exposes darker sea and land that absorb more heat (ice–albedo feedback), and thawing permafrost can release stored carbon as CO₂ and methane.
• Ocean acidification is the "other CO₂ problem": the oceans absorb roughly a quarter of the CO₂ we emit, forming carbonic acid, which lowers the pH of sea water and makes it harder for corals, molluscs and some plankton to build calcium carbonate shells and skeletons.

Both treaties rest on the UNFCCC principle of common but differentiated responsibilities and respective capabilities (CBDR–RC): every country shares the duty to act, but those that emitted most historically and can afford most should do most. India ratified the Paris Agreement on 2 October 2016. Its first NDC (2015) pledged a 33–35% cut in the emission intensity of GDP by 2030 from 2005 levels and 40% of installed power capacity from non-fossil sources — the latter reached in 2021, years early. The updated NDC (2022) raised these to 45% and about 50%, and kept the pledge of an additional carbon sink of 2.5–3 billion tonnes of CO₂-equivalent through more forest and tree cover by 2030. At COP-26 India announced the "Panchamrit", including 500 GW of non-fossil capacity by 2030 and net-zero emissions by 2070, and it submitted its Long-Term Low-Emission Development Strategy at COP-27.

• International Solar Alliance — launched by India and France at COP-21 in Paris (2015); headquarters at Gurugram, Haryana.
• Coalition for Disaster Resilient Infrastructure (CDRI) — launched by India at the UN Climate Action Summit in New York (2019); secretariat in New Delhi.
• Mission LiFE (Lifestyle for Environment) — launched in 2022 to promote individual and community behaviour that uses resources mindfully.

The Convention on Biological Diversity (CBD), opened at Rio in 1992 and in force from 1993, has three objectives: conservation of biodiversity, sustainable use of its components, and fair and equitable sharing of benefits from genetic resources. Two protocols sit under it: the Cartagena Protocol on Biosafety (adopted 2000, in force 2003), on the safe transfer of living modified organisms, and the Nagoya Protocol (adopted 2010, in force 2014), on access and benefit-sharing. The 2010 Aichi Biodiversity Targets (twenty, for 2011–2020) were followed in December 2022 by the Kunming–Montreal Global Biodiversity Framework, with 23 targets for 2030 — the best known being "30 by 30", to conserve 30% of the world's land and 30% of its oceans by 2030. India hosted CBD COP-11 at Hyderabad in 2012. The United States is not a party to the CBD.

The National Action Plan on Climate Change (NAPCC) was released on 30 June 2008 by the Prime Minister's Council on Climate Change. It does not set emission caps; it organises India's response through eight National Missions, each led by a ministry, that are meant to deliver development and climate benefits together. States prepare their own State Action Plans on Climate Change, and a National Adaptation Fund for Climate Change (2015) finances adaptation projects in vulnerable sectors.

A carbon market puts a price on emissions so that cuts happen wherever they are cheapest. The unit is the carbon credit: one tonne of CO₂ or its equivalent in another greenhouse gas. In a cap-and-trade system a regulator fixes a total cap and issues allowances; a firm that cuts more than it must can sell its spare allowances to one that cuts less. In a baseline-and-credit system a project earns credits for reducing emissions below what would otherwise have happened. Compliance markets are created by law; voluntary markets serve companies and individuals offsetting by choice, and their quality depends heavily on whether the reductions are real, additional and permanent.

India is building a domestic market. The Energy Conservation (Amendment) Act, 2022 empowered the Central government to specify a carbon-credit trading scheme, and the Carbon Credit Trading Scheme, 2023 was notified under the Energy Conservation Act, 2001. It creates the Indian Carbon Market, with the Bureau of Energy Efficiency as administrator: obligated industries receive greenhouse-gas emission-intensity targets and can trade carbon credit certificates, alongside an offset mechanism for voluntary projects. It builds on older market instruments — the PAT scheme's Energy Saving Certificates and Renewable Energy Certificates. Separately, the Green Credit Programme (2023), notified under the Environment (Protection) Act, rewards actions such as tree planting and water conservation with green credits; it is an environmental incentive, not a carbon credit. India also taxed coal through a cess introduced in 2010, later subsumed into the GST compensation cess in 2017.

• REDD+ — Reducing Emissions from Deforestation and forest Degradation, plus conservation, sustainable management of forests and enhancement of forest carbon stocks: results-based payments to developing countries for keeping forests standing.
• Carbon Border Adjustment Mechanism (CBAM) — the European Union's charge on the embedded carbon of certain imports such as steel, aluminium and cement; reporting began in October 2023, with financial obligations from 2026. It matters to Indian exporters because it prices carbon at the border.