People, Development & Environment

Human beings do not sit outside nature; they are one species inside it that has learned to change the rest at scale. Anything caused by human activity is called anthropogenic (from Greek anthropos, "human"). Geographers describe the relation between people and nature through three classical positions.

1. Environmental determinism: nature dictates, humans obey. Climate and terrain are said to decide culture and even character. Dominant in early geography; now considered simplistic.
2. Possibilism: nature offers a set of possibilities; human choice and technology select among them. Two societies in the same valley may live very differently.
3. Neo-determinism (stop-and-go determinism): proposed by Griffith Taylor — humans may go fast where nature permits and must slow down where it warns. A middle path that today underpins sustainability thinking.

The main anthropogenic drivers of environmental change are worth memorising as a chain, because every later section of this chapter is a consequence of one of them: population growth and urbanisation → industrialisation and fossil-fuel energy → intensive agriculture → deforestation and land-use change → mining and construction → transport → consumption and waste generation.

Pollution is the addition of any substance or form of energy to the environment at a rate faster than it can be dispersed, diluted, broken down or recycled. Environmental issues are classified by scale: local (a noisy market, a contaminated well), regional (acid rain, river pollution, transboundary smog) and global (climate change, ozone depletion, ocean plastic).

Pollutants are also divided into primary pollutants, emitted directly from a source (SO₂, NO, CO, particulates), and secondary pollutants, formed in the atmosphere by reaction — the classic example being ground-level ozone and PAN (peroxyacetyl nitrate) in photochemical smog. Non-biodegradable pollutants such as DDT, mercury and plastics persist and undergo bioaccumulation in an organism and biomagnification up the food chain.

India regulates ambient air through the National Ambient Air Quality Standards (NAAQS) notified by the Central Pollution Control Board — the current set dates from 2009 and covers 12 pollutants. For public communication, the National Air Quality Index (AQI) was launched under the "One Number, One Colour, One Description" idea and aggregates eight pollutants: PM₁₀, PM₂.₅, NO₂, SO₂, CO, O₃, NH₃ and Pb. The AQI reported for a place is the worst (highest) sub-index among these, and that pollutant is called the prominent pollutant.

Water pollution is measured chiefly by BOD (biochemical oxygen demand) — the oxygen microbes need to decompose organic matter — and COD (chemical oxygen demand). High BOD means low dissolved oxygen (DO), which suffocates fish. Soil pollution arises from pesticides, heavy metals, industrial sludge and excess salts, and shows up as loss of fertility, salinity and contaminated crops. Noise pollution is unique in leaving no residue: it is measured in decibels (dB) on a logarithmic scale, and India's Noise Pollution (Regulation and Control) Rules, 2000 set daytime limits of about 75 dB in industrial, 65 dB in commercial, 55 dB in residential and 50 dB in silence zones, with night limits lower.

Waste management in India is governed by a family of rules notified under the Environment (Protection) Act, 1986 — most of them re-issued in 2016. The organising principle everywhere is the waste hierarchy, best remembered as the 5 Rs: Refuse → Reduce → Reuse → Recycle → Recover, with landfill and incineration only as the last resort. A second organising principle is Extended Producer Responsibility (EPR): the producer of a product remains responsible for taking it back at end of life.

• Composting and vermicomposting: aerobic decomposition of wet waste into manure — the cheapest and most decentralised solution for Indian cities.
• Biomethanation: anaerobic digestion producing biogas (methane) plus slurry; used in gaushalas, canteens and STPs.
• Waste-to-energy / incineration: reduces volume drastically but risks dioxin and furan emission if temperature and scrubbing are inadequate.
• Sanitary landfill: engineered pit with liner, leachate collection and gas venting — very different from an open dump, which contaminates groundwater through leachate.

The greenhouse effect is natural and necessary: certain gases in the troposphere let short-wave solar radiation in but absorb the long-wave infrared radiation the Earth re-emits, keeping the planet roughly 33 °C warmer than it would otherwise be. Global warming is the enhanced greenhouse effect caused by anthropogenic emissions. Climate change is the wider, long-term shift in temperature, rainfall, monsoon behaviour, sea level and extreme-event frequency that follows.

Global Warming Potential (GWP) compares how much heat one kilogram of a gas traps relative to one kilogram of CO₂ over a chosen horizon, usually 100 years. By definition CO₂ has a GWP of 1. Methane traps far more heat per kilogram but survives only about a decade in the atmosphere, while CO₂ persists for centuries — which is why CO₂ still dominates total forcing despite its low GWP. (Exact GWP values are revised in each IPCC assessment report, so quote the report you rely on rather than a single number.)

Ozone depletion is a completely separate problem, and confusing it with global warming is the single most common error in this unit. The ozone layer lies in the stratosphere, roughly 15–35 km up, and absorbs harmful UV-B radiation. Chlorofluorocarbons (CFCs), halons, carbon tetrachloride and methyl bromide drift up, are split by UV light to release chlorine and bromine free radicals, and each such radical destroys thousands of ozone molecules catalytically. Thickness is measured in Dobson Units; the seasonal spring "ozone hole" over Antarctica forms because polar stratospheric clouds concentrate the reaction. World Ozone Day is 16 September.

• Acid rain: SO₂ and NOₓ dissolve in atmospheric moisture to form sulphuric and nitric acid, bringing rainfall with pH below the natural value of about 5.6. Effects: leaching of soil nutrients, fish kill in lakes, and corrosion of marble — the "stone leprosy" blamed for damage to the Taj Mahal.
• Eutrophication: nitrate and phosphate enrichment of a water body triggers algal bloom; the bloom blocks light, then dies and decomposes, raising BOD and crashing dissolved oxygen until fish suffocate. The end state is a dead zone. Cultural (human-caused) eutrophication is far faster than the natural kind.
• Deforestation: removal of forest cover for agriculture, mining, roads, dams and settlements. It converts a carbon sink into a carbon source, accelerates soil erosion and flash floods, and reduces rainfall by cutting evapotranspiration.
• Biodiversity loss: driven by HIPPO — Habitat loss, Invasive species, Pollution, Population growth and Overexploitation. The IUCN Red List grades species from Least Concern up through Vulnerable, Endangered and Critically Endangered to Extinct.

A resource is anything in nature that human ability and technology can turn to use. The basic classification for the exam is by renewability: renewable (flow) resources replenish on a human timescale — solar, wind, hydro, geothermal, biomass, tidal; non-renewable (stock) resources exist in fixed quantity — coal, petroleum, natural gas, uranium and metallic minerals. Note the standard subtlety: renewable resources can still be exhausted if used faster than they regenerate (groundwater, forests, fisheries), so "renewable" is not the same as "inexhaustible".

India's institutional push runs through the Ministry of New and Renewable Energy (MNRE), the Jawaharlal Nehru National Solar Mission launched in 2010 as one of the eight missions of the National Action Plan on Climate Change (2008), and the International Solar Alliance (ISA), jointly launched by India and France in 2015 with its headquarters at Gurugram. On the efficiency side, the Energy Conservation Act, 2001 created the Bureau of Energy Efficiency (BEE), which runs the familiar star labelling scheme for appliances and the Perform, Achieve and Trade (PAT) scheme for industry.

A hazard is a potentially damaging phenomenon; a disaster is what happens when that hazard actually strikes a vulnerable exposed community and overwhelms its coping capacity. The standard relation is Risk = Hazard × Vulnerability ÷ Capacity. An earthquake in an empty desert is a hazard event, not a disaster — which is why disaster management works mainly on vulnerability and capacity, the only two terms humans can change.

The disaster-management cycle has four phases, and NET repeatedly asks which activity belongs to which phase. Two phases come before the event and two after it.

1. Mitigation (before): structural and non-structural steps to reduce the hazard's impact permanently — earthquake-resistant building codes, embankments, land-use zoning, afforestation, hazard mapping.
2. Preparedness (before): getting ready for the event that will still occur — early-warning systems, evacuation drills, cyclone shelters, stockpiling, training and community awareness.
3. Response (after, immediate): search and rescue, evacuation, relief camps, medical aid, restoring drinking water and communication. This is the NDRF's prime role.
4. Recovery / rehabilitation and reconstruction (after, long term): rebuilding houses, livelihoods and infrastructure — ideally following the principle of "build back better".

India's legal framework is the Disaster Management Act, 2005, which created a three-tier structure: the National Disaster Management Authority (NDMA) chaired ex officio by the Prime Minister, State Disaster Management Authorities chaired by Chief Ministers, and District Authorities. The National Disaster Response Force (NDRF) is the specialist response force, and the National Institute of Disaster Management (NIDM) handles training and capacity building. Internationally, the Sendai Framework for Disaster Risk Reduction 2015–2030 was adopted at the Third UN World Conference in Sendai, Japan, in March 2015, replacing the Hyogo Framework for Action (2005–2015); it has four priorities for action and seven global targets, and shifts the emphasis from managing disasters to managing risk.

The Constitution gives environmental protection a firm footing through the 42nd Amendment (1976), which inserted 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 environment). The Supreme Court has read the right to a clean environment into Article 21, the right to life. Statutory law then follows in six landmark Acts whose years are pure recall marks in NET.

On the institutional side, the Central Pollution Control Board (CPCB) was constituted in 1974 under the Water Act and works under the Ministry of Environment, Forest and Climate Change; State Pollution Control Boards (SPCBs) issue consents, monitor and prosecute at state level. Environmental Impact Assessment (EIA) is the process of predicting the environmental consequences of a proposed project before clearance, and in India it is governed by the EIA Notification of 2006 issued under the 1986 Act, which sorts projects into Category A (appraised at the Centre) and Category B (appraised at state level).

1. Screening — is an EIA required at all for this project?
2. Scoping — which impacts and which alternatives must the study examine? Produces the Terms of Reference.
3. Public consultation / public hearing — affected people and the wider public place their concerns on record.
4. Appraisal and decision — an Expert Appraisal Committee recommends, and the regulatory authority grants or refuses environmental clearance with conditions; post-clearance monitoring follows.

This is the highest-yield table in Unit 9. Learn it as a timeline of subjects, not as isolated dates: wetlands (1971) → the first global conference (1972) → trade in species (1973) → the ozone treaties (1985 and 1987) → hazardous waste (1989) → the Earth Summit and its twin conventions (1992) → binding emission cuts (1997) → voluntary national pledges (2015).

Sitting behind all of this is the Intergovernmental Panel on Climate Change (IPCC), established in 1988 by the World Meteorological Organization (WMO) and UNEP. The IPCC does no original research and monitors nothing: it assesses published science and issues Assessment Reports through three working groups (physical science; impacts and adaptation; mitigation). Its reports set the factual baseline that negotiators at the annual Conference of the Parties (COP) argue over. Two principles from the UNFCCC recur in questions: "common but differentiated responsibilities and respective capabilities" (CBDR-RC) and the polluter-pays and precautionary principles.