A river stretch with a very high biochemical oxygen demand (BOD) indicates:

A heavy load of organic pollution and low dissolved oxygen

High arsenic concentration from groundwater

A heavy load of organic pollution and low dissolved oxygen

Article 48A, which directs the State to protect and improve the environment, was inserted into the Constitution by:

The original Constitution of 1950

Which umbrella legislation was enacted in the wake of the Bhopal gas disaster?

Environment (Protection) Act, 1986

Forest (Conservation) Act, 1980

Environment (Protection) Act, 1986

Water (Prevention and Control of Pollution) Act, 1974

Assertion (A): Under the Paris Agreement every party must prepare and communicate nationally determined contributions. Reason (R): The Kyoto Protocol set legally binding emission targets only for developed (Annex I) countries. Choose the correct option.

Both A and R are true, but R is not the correct explanation of A

Both A and R are true, and R is the correct explanation of A

Both A and R are true, but R is not the correct explanation of A

The long-term temperature goal of the Paris Agreement is to hold global warming:

Well below 2 °C above pre-industrial levels, pursuing efforts to limit it to 1.5 °C

Geography of Environment II: Environmental Hazards, National Programmes and Policies, and International Treaties

The second half of Unit IV moves from how ecosystems work to how they are damaged and governed. The document lists five environmental hazards and disasters — global warming, the urban heat island, atmospheric pollution, water pollution and land degradation — then national programmes and policies (the legal framework and environmental policy), and finally international treaties and programmes, naming the Brundtland Commission, the Kyoto Protocol, Agenda 21, the Sustainable Development Goals and the Paris Agreement. Years and legal provisions are tested exactly, so this chapter gives them precisely, and it explains the geography behind each hazard rather than only its definition.

1. Global warming and the urban heat island

Global warming is the enhancement of the natural greenhouse effect by greenhouse gases added by human activity. Each gas is weighted by its global warming potential (GWP) relative to carbon dioxide over 100 years — methane roughly 28 and nitrous oxide roughly 265 in the IPCC's Fifth Assessment values — so a smaller emission of methane or of fluorinated gases can matter as much as a larger one of CO₂. The geographical consequences are uneven: the Arctic is warming about three to four times as fast as the global average (Arctic amplification), glaciers are retreating across the Himalaya, extreme heat and heavy rainfall are becoming more frequent, and low-lying coasts and islands face rising seas.

The urban heat island (UHI) is the excess warmth of a city over its rural surroundings, first recorded for London by Luke Howard in the early nineteenth century. Its causes are all geographical: dark, sealed surfaces of asphalt and concrete with low albedo and high heat storage; the replacement of vegetation and moist soil, which removes the cooling of evapotranspiration; street canyons that trap long-wave radiation and cut wind speed; anthropogenic heat from vehicles, air conditioners and industry; and a pollution dome that traps outgoing radiation. The UHI is strongest at night and on calm, clear days, when rural areas cool quickly and the city releases its stored heat slowly; its intensity grows with city size. Cool and green roofs, urban forests, water bodies and wider street spacing are the standard mitigation measures, and several Indian cities now include them in heat action plans — the first was Ahmedabad's, in 2013.

⚠️ The heat island is a night-time phenomenon first

A question may ask when the urban–rural temperature difference is greatest. The answer is a calm, clear night, not a sunny afternoon: by day both city and country heat up, but after sunset the country cools rapidly while buildings and pavements keep releasing heat.

2. Atmospheric pollution, water pollution and land degradation

Atmospheric pollutants are primary — emitted directly, such as sulphur dioxide, nitrogen oxides, carbon monoxide, particulate matter and volatile organic compounds — or secondary, formed in the air, such as ground-level ozone, peroxyacetyl nitrate and sulphate and nitrate aerosols. Two kinds of smog illustrate the difference: the London smog of December 1952, a sulphurous, reducing smog of coal smoke and fog under a winter inversion that killed thousands, and the photochemical smog of Los Angeles, formed when sunlight acts on vehicle nitrogen oxides and hydrocarbons. Sulphur and nitrogen oxides also produce acid rain (rain below the natural pH of about 5.6). India notified revised National Ambient Air Quality Standards for twelve pollutants in 2009, launched a National Air Quality Index in 2014 covering eight pollutants, and began the National Clean Air Programme (NCAP) in 2019 to cut particulate concentrations in non-attainment cities.

Water pollution comes from point sources (sewage outfalls, factory effluents) and non-point sources (runoff of fertilisers, pesticides and animal waste from farmland), the latter harder to regulate. Organic pollution is measured by biochemical oxygen demand (BOD) — the oxygen microbes need to decompose the organic matter — and chemical oxygen demand; a high BOD means a heavy organic load and low dissolved oxygen for aquatic life. Excess nitrogen and phosphorus cause eutrophication: algal blooms, oxygen depletion when they decay, and fish kills. Groundwater brings geogenic hazards too: arsenic in the aquifers of the Ganga–Brahmaputra delta and plains (West Bengal, Bihar, Bangladesh) and fluoride in parts of Rajasthan, Telangana and elsewhere. Land degradation is the decline of land's productive capacity through water and wind erosion, salinisation and waterlogging (often from canal irrigation without drainage), loss of vegetation, and mining; in drylands it is called desertification. The ISRO Space Applications Centre's atlas estimated that about 30 per cent of India's geographical area was degraded in 2018–19, with water erosion the leading process.

3. National programmes and policies: the legal framework

The Constitution was amended by the 42nd Amendment (1976) to add Article 48A, a Directive Principle requiring the State to protect and improve the environment and safeguard forests and wildlife, and Article 51A(g), a Fundamental Duty of every citizen to protect the natural environment. The Supreme Court has read the right to a wholesome environment into the right to life under Article 21, and has adopted the polluter-pays and precautionary principles (Vellore Citizens' Welfare Forum, 1996) as part of Indian law.

Law or policy	Year	Significance
Wildlife (Protection) Act	1972	Schedules of protected species; national parks and sanctuaries
Water (Prevention and Control of Pollution) Act	1974	Created the Central and State Pollution Control Boards
Forest (Conservation) Act	1980	Central approval needed to divert forest land to other uses
Air (Prevention and Control of Pollution) Act	1981	Air quality regulation through the pollution control boards
Environment (Protection) Act	1986	Umbrella law passed after the Bhopal gas disaster of 1984; basis of EIA notifications (1994, 2006)
National Forest Policy	1988	Goal of one-third of the land under forest or tree cover (two-thirds in the hills)
Biological Diversity Act	2002	Implements the Convention on Biological Diversity; access and benefit-sharing
National Environment Policy	2006	Mainstreams environment into development planning
National Action Plan on Climate Change	2008	Eight national missions, including solar, energy efficiency, water, the Himalayan ecosystem and Green India
National Green Tribunal Act	2010	A specialised tribunal for environmental disputes

4. International treaties and programmes

The modern sequence begins with the UN Conference on the Human Environment at Stockholm (1972), which created the UN Environment Programme. The World Commission on Environment and Development, chaired by Norway's Gro Harlem Brundtland and hence the Brundtland Commission, published Our Common Future (1987) with the definition that anchors everything after it: sustainable development is "development that meets the needs of the present without compromising the ability of future generations to meet their own needs". The same year the Montreal Protocol (1987) began phasing out ozone-depleting substances; its Kigali Amendment (2016) extended it to hydrofluorocarbons. The UN Conference on Environment and Development — the Rio Earth Summit (1992) — adopted Agenda 21, a non-binding action plan for sustainable development in the twenty-first century with a strong emphasis on local action (Local Agenda 21), together with the Rio Declaration and the Forest Principles, and opened for signature the UN Framework Convention on Climate Change (UNFCCC) and the Convention on Biological Diversity; the Convention to Combat Desertification followed in 1994.

Instrument	Year	Key content
Kyoto Protocol (to the UNFCCC)	Adopted 1997; in force 2005	Legally binding cuts for developed (Annex I) countries — on average 5.2 per cent below 1990 levels in 2008–2012; flexible mechanisms: emissions trading, Joint Implementation and the Clean Development Mechanism; a second period to 2020 under the Doha Amendment (2012)
Millennium Development Goals	2000	Eight goals to 2015, aimed mainly at developing countries
Sustainable Development Goals (2030 Agenda)	2015	17 goals and 169 targets for all countries, from ending poverty (Goal 1) to climate action (Goal 13) and partnerships (Goal 17)
Paris Agreement (COP21)	Adopted 2015; in force 2016	Hold warming well below 2 °C and pursue 1.5 °C; every party submits nationally determined contributions (NDCs), updated every five years; a global stocktake (first in 2023)

The shift from Kyoto to Paris is the key conceptual point. Kyoto was top-down and divided the world into developed countries with binding targets and developing countries with none, applying the principle of common but differentiated responsibilities. Paris is bottom-up: every country sets its own target, and the obligation is procedural — to submit, implement and progressively strengthen it. India's updated NDC (2022) commits to reduce the emissions intensity of its GDP by 45 per cent from the 2005 level by 2030 and to reach about 50 per cent of installed electric power capacity from non-fossil sources by 2030, and at Glasgow (COP26, 2021) India announced a net-zero target for 2070.

🧠 Four dates that are always asked

1987 — Brundtland (Our Common Future) and Montreal. 1992 — Rio: Agenda 21, UNFCCC, CBD. 1997 — Kyoto (in force 2005). 2015 — both the SDGs (September, New York) and the Paris Agreement (December, COP21). A question pairing Agenda 21 with Kyoto, or the SDGs with 2000, is testing exactly these.

Key takeaways

Global warming weights gases by GWP (methane about 28, nitrous oxide about 265 over 100 years); the urban heat island comes from low albedo, lost evapotranspiration, street canyons and waste heat, and is strongest on calm, clear nights.
Primary pollutants are emitted directly, secondary ones (ozone, PAN) form in the air; London 1952 was sulphurous smog, Los Angeles photochemical; India has NAAQS (2009), the AQI (2014) and NCAP (2019).
High BOD means heavy organic pollution; nutrients cause eutrophication; arsenic afflicts the Ganga–Brahmaputra aquifers; about 30 per cent of India's area was degraded in 2018–19, mostly by water erosion.
Articles 48A and 51A(g) came with the 42nd Amendment (1976); the Water (1974), Air (1981) and umbrella Environment (Protection) Act (1986, after Bhopal); NAPCC (2008) has eight missions; the NGT dates from 2010.
Stockholm 1972, Brundtland and Montreal 1987, Rio and Agenda 21 1992, Kyoto 1997 (binding for Annex I), SDGs and Paris 2015 (NDCs for all); India: 45 per cent intensity cut by 2030 and net zero by 2070.

Practice questions (10)

Attempt each one before opening the answer. Every explanation names the tempting wrong option as well as the right one, because that is where marks are lost.

The report Our Common Future, which defined sustainable development, was published by the Brundtland Commission in:
1. 1992
2. 1972
3. 1997
4. 1987
Show answer
Answer: D — 1987
The World Commission on Environment and Development published Our Common Future in 1987. 1972 is Stockholm, 1992 is the Rio Earth Summit and 1997 the Kyoto Protocol.
The Kyoto Protocol was adopted in 1997 and entered into force in:
1. 2005
2. 1999
3. 2012
4. 2008
Show answer
Answer: A — 2005
The Protocol needed ratification by countries covering 55 per cent of Annex I emissions; Russia's ratification brought it into force on 16 February 2005. Its first commitment period ran from 2008 to 2012.
A river stretch with a very high biochemical oxygen demand (BOD) indicates:
1. Clean water rich in oxygen
2. High arsenic concentration from groundwater
3. A heavy load of organic pollution and low dissolved oxygen
4. Acid rain in the catchment
Show answer
Answer: C — A heavy load of organic pollution and low dissolved oxygen
BOD measures the oxygen that microbes consume while decomposing organic matter. A high value means plenty of sewage or organic waste, which draws down dissolved oxygen and stresses fish. Arsenic is a geogenic, non-organic contaminant.
Which of the following were adopted or opened for signature at the Rio Earth Summit of 1992? Select all that apply.
1. The Convention on Biological Diversity
2. The Montreal Protocol
3. Agenda 21
4. The UN Framework Convention on Climate Change
Show answer
Answer: A — The Convention on Biological Diversity; C — Agenda 21; D — The UN Framework Convention on Climate Change
Rio 1992 produced Agenda 21, the Rio Declaration and the Forest Principles, and opened the UNFCCC and the CBD for signature. The Montreal Protocol on ozone-depleting substances dates from 1987.
The difference in temperature between a city and its rural surroundings is usually greatest:
1. On windy, overcast afternoons
2. At sunrise on cloudy days
3. On calm, clear nights
4. During heavy monsoon rain
Show answer
Answer: C — On calm, clear nights
Clear skies let the countryside lose heat rapidly by radiation, and calm air prevents mixing, while the city's buildings and paving release the heat they stored by day. Wind and cloud both reduce the contrast.
Article 48A, which directs the State to protect and improve the environment, was inserted into the Constitution by:
1. The 44th Amendment, 1978
2. The 73rd Amendment, 1992
3. The original Constitution of 1950
4. The 42nd Amendment, 1976
Show answer
Answer: D — The 42nd Amendment, 1976
The 42nd Amendment (1976), in the wake of the Stockholm Conference, added both Article 48A (a Directive Principle) and Article 51A(g) (a Fundamental Duty to protect the natural environment).
Which umbrella legislation was enacted in the wake of the Bhopal gas disaster?
1. Forest (Conservation) Act, 1980
2. Environment (Protection) Act, 1986
3. Water (Prevention and Control of Pollution) Act, 1974
4. Biological Diversity Act, 2002
Show answer
Answer: B — Environment (Protection) Act, 1986
The December 1984 disaster exposed the gaps in sector-specific laws; the Environment (Protection) Act, 1986 gave the Centre broad powers and is the basis of the EIA notifications. The Water and Forest Acts predate Bhopal.
Assertion (A): Under the Paris Agreement every party must prepare and communicate nationally determined contributions. Reason (R): The Kyoto Protocol set legally binding emission targets only for developed (Annex I) countries. Choose the correct option.
1. Both A and R are true, and R is the correct explanation of A
2. Both A and R are true, but R is not the correct explanation of A
3. A is true, but R is false
4. A is false, but R is true
Show answer
Answer: B — Both A and R are true, but R is not the correct explanation of A
Both statements are true, but R describes Kyoto's design and does not explain why Paris requires NDCs from all parties. The two are related as contrast — top-down targets for some versus self-set pledges for everyone — not as cause and effect.
The long-term temperature goal of the Paris Agreement is to hold global warming:
1. Well below 2 °C above pre-industrial levels, pursuing efforts to limit it to 1.5 °C
2. Below 3 °C by 2100
3. At 1990 levels
4. Below 1 °C by 2030
Show answer
Answer: A — Well below 2 °C above pre-industrial levels, pursuing efforts to limit it to 1.5 °C
Article 2 of the Paris Agreement sets the goal of well below 2 °C with efforts towards 1.5 °C. "1990 levels" is the Kyoto baseline for emissions, not a temperature goal.
How many goals make up the Sustainable Development Goals adopted by the United Nations in 2015? Type a number.
Numerical answer — type the value.
Show answer
Answer: 17
The 2030 Agenda sets 17 goals with 169 targets, applying to all countries. Its predecessor, the Millennium Development Goals of 2000, had eight goals to 2015.