Geographical Issues: Pollution, Urban Waste, Slums and Land Degradation

1. Environmental pollution: meaning, classification and the legal frame

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• Environmental pollution is the release of substances and energy from the waste of human activities. It harms living things and property. It is classified by the medium that carries and spreads the pollutants (Class 12, Geographical Perspective on Selected Issues and Problems).
• Four types (Table 9.1):
• Air: oxides of sulphur and nitrogen, CO, hydrocarbons, ammonia, lead, asbestos and beryllium. These come from burning coal, petrol and diesel, from industry, and from waste and sewage disposal.
• Water: solids, nitrates, fluoride, oil, pesticides, coliforms, heavy metals and radioactive substances. These come from sewage, urban and farm run-off, industries and nuclear plants.
• Land: excreta, garbage, pesticide and fertiliser residues, fluorides and radioactive matter.

• Noise: aircraft, vehicles, trains, industry and advertising media.

• Pollution vs pollutants: pollution is the harmful condition. Pollutants are the substances that cause it.

• Legal frame (beyond NCERT):
• The Water Act 1974 created the Central Pollution Control Board (CPCB) and the state boards. With the state boards, the CPCB monitors water and air quality. (NCERT: 507 water stations; now several thousand, verify current.)
• The Air Act came in 1981.
• The Environment (Protection) Act 1986 is an umbrella law passed after the Bhopal gas tragedy (1984). It lets the Centre set emission and discharge standards and control hazardous substances.

• The National Green Tribunal was set up in 2010.

• The same theme runs through every law: weak enforcement.

2. Water pollution: sources, measurement and health

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• Water pollution: surface water is never pure. It becomes polluted when suspended, organic and inorganic substances go beyond water's self-purifying capacity, meaning its natural ability to clean itself.
• Natural sources (erosion, landslides, decay of plants and animals) matter less than human ones.
• Human sources:
• Industry is the biggest. Leather, pulp and paper, textiles and chemical units dump effluents and heavy metals.
• Agriculture: fertilisers raise nitrates, and pesticides seep into groundwater.

• Cultural activities: pilgrimages, religious fairs and tourism.

• NCERT says almost all surface water in India is unfit to drink without treatment.

• Water-borne diseases: diarrhoea, intestinal worms, hepatitis, typhoid and cholera. WHO says about one-fourth of India's communicable diseases are water-borne.
• Biochemical oxygen demand (BOD): the oxygen that microbes use to break down organic matter. Bathing-quality water should have BOD of 3 mg/l or less.
• Polluted river stretches: stretches where BOD is above 3 mg/l. CPCB (2022) found 311 such stretches on 279 rivers. Maharashtra has the most (verify current).
• Sewage treatment gap: cities produced about 72,000 MLD (million litres a day) of sewage in 2020-21 but treated only about 28% (CPCB; verify current).
• Water (Prevention and Control of Pollution) Act 1974: factories need consent before they discharge effluent. Earlier NCERT noted 251 polluting industries along rivers and lakes (1997).

3. The Ganga and the Yamuna: polluted stretches and river cleaning

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River	Polluted stretches	Main causes
Ganga (UP, Bihar, West Bengal)	Downstream of Kanpur; downstream of Varanasi; Farakka barrage	Industries such as Kanpur's tanneries; domestic sewage of Kanpur, Prayagraj, Varanasi, Patna and Kolkata
Yamuna (Delhi, UP)	Delhi to the Chambal confluence; Mathura and Agra	Haryana and UP take water for irrigation, so little water is left to dilute waste; farm run-off brings micro-pollutants; Delhi's domestic and industrial waste flows in (toxic foam)

• Ganga pollution and Yamuna pollution are the textbook cases. NCERT's MCQ answer is that the Yamuna is highly polluted.
• Ganga Action Plan (1985): India's first river-cleaning plan. It aimed to catch and treat sewage but had limited success. It was followed by GAP-II, the Yamuna Action Plan (1993) and the National Ganga River Basin Authority (2009).
• National Mission for Clean Ganga (NMCG): a registered society set up in 2011. It is the working arm of the National Ganga Council (2016).
• Namami Gange Programme: a flagship scheme approved in June 2014. Its aims are:
• sewage treatment in towns
• monitoring of industrial effluents
• river-front development
• planting trees along the banks
• cleaning the river surface
• Ganga Grams in Uttarakhand, UP, Bihar, Jharkhand and West Bengal

• public awareness against pollution from rituals

• Results so far: dissolved oxygen has improved, but faecal coliform (bacteria from human waste) is still high (verify current).

4. Air pollution: sources, smog, acid rain and Delhi's winter crisis

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• Air pollution: dust, fumes, gas, fog, odour, smoke or vapour added to the air in amounts and for times that harm plants, animals and property.
• Main sources: burning fossil fuels, mining and industry. These release oxides of sulphur and nitrogen, hydrocarbons, CO₂, CO, lead and asbestos. Beyond NCERT, add vehicles, construction dust, burning of biomass and waste, and brick kilns.
• Effects: diseases of the breathing, nervous and circulatory (heart and blood) systems.
• Smog: smoky fog over cities caused by pollution. It is very harmful to health.
• Acid rain: rain with pH below about 5.6. It forms when sulphur and nitrogen oxides turn into acids.
• NCERT fact: in cities, the first rain after summer always has a lower pH than later rains.

• It damages soils, lakes, forests and monuments. Example: the Taj Mahal, threatened by the Mathura refinery. The Supreme Court created the Taj Trapezium Zone in 1996 (M.C. Mehta case).

• Delhi winter smog (November–January):

• Pollution from vehicles, dust, industry and waste burning builds up over the city.
• Temperature inversion (cold air sits near the ground under warmer air), low mixing height and calm winds trap it.

• North-westerly winds carry crop smoke and firecracker smoke down the Indo-Gangetic plain.

• Stubble burning: farmers in Punjab, Haryana and western UP burn paddy straw in October–November. They do this to clear fields fast for wheat, because combine machines leave stubble behind and the 2009 rule on late transplanting leaves little time before sowing.

• Fixes: Happy Seeder machines, bio-decomposer sprays, straw for power plants and pellets, and moving away from paddy.

5. Air quality standards and clean-air governance

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• National Ambient Air Quality Standards (NAAQS): set by CPCB in 2009 for 12 pollutants. The PM2.5 limit is 60 µg/m³ (24-hour) and 40 (annual). WHO's 2021 guidelines are much stricter: 15 and 5.
• National Air Quality Index (AQI): launched in April 2015.
• It combines eight pollutants into one number: PM10, PM2.5, NO₂, SO₂, CO, ozone, ammonia and lead.

• It has six bands: Good (0–50), Satisfactory, Moderately polluted, Poor, Very Poor and Severe (401–500).

• Non-attainment city: a city that failed NAAQS for PM10 or NO₂ for five years in a row (2011–15).

• National Clean Air Programme (NCAP): launched in January 2019. It covers 131 non-attainment cities, each with its own action plan.
• Target: cut PM10 by up to 40% by 2025-26, compared with 2017-18 levels.

• Funds are linked to performance. Cities are ranked each year in the Swachh Vayu Survekshan (verify current).

• Most non-attainment cities lie in the Indo-Gangetic plain. It is a landlocked basin with winter inversions and dust.

• Graded Response Action Plan (GRAP): first notified in 2017. It has four stages based on AQI: Poor, Very Poor, Severe and Severe+. Measures range from dust control to bans on construction, diesel generators and trucks entering Delhi.
• Commission for Air Quality Management (CAQM): set up by an Act in 2021, replacing EPCA. It covers Delhi, Punjab, Haryana, Rajasthan and UP.
• Debate: should air be managed across a whole airshed (the shared region of air) or city by city?

6. Noise pollution and land pollution

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• Noise pollution: sound that is unbearable and uncomfortable. It became a serious concern only recently, because of new technology. It is measured in decibels (dB).
• Sources: factories, building and demolition machines, vehicles and aircraft, and sirens and loudspeakers at festivals.
• Traffic is the biggest nuisance. How bad it is depends on the type of vehicle, aircraft or train and on the condition of roads and vehicles.
• At sea, noise stays in harbours, from loading and unloading.

• Fig. 9.2 shows noise monitoring at the Panchpatmali bauxite mine (Odisha).

• Noise is location-specific. It fades with distance from industrial areas, highways and airports, and it is a hazard in metros.

• Noise pollution standards (Noise Rules 2000), day/night limits in dB(A):

Zone	Day	Night
Industrial	75	70
Commercial	65	55
Residential	55	45
Silence zone (100 m around hospitals, schools, courts)	50	40

• Loudspeakers are banned from 10 pm to 6 am (Supreme Court, 2005).
• Land pollution: land contaminated by excreta, viruses and bacteria, garbage, untreated industrial waste, pesticide and fertiliser residues, fluorides and radioactive matter. It lowers fertility and enters food chains and groundwater.

7. Urban waste disposal and the new waste rules

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• Solid waste: old and used articles such as metal scraps, broken glass, plastic containers, polythene bags, ash and CDs. It is also called refuse, garbage or rubbish. It comes from households and from industries and shops.
• Urban waste disposal:
• Household waste goes to public land or contractors' sites.
• Industrial waste goes to municipal landfills in low-lying ground.

• Ash and debris come from thermal plants and construction.

• Health hazards: bad smell, plus flies and rodents that spread typhoid, diphtheria, diarrhoea, malaria and cholera.

• Collection gap: metros (Mumbai, Kolkata, Chennai, Bengaluru) collect about 90% of their waste. Many other towns leave 30–50% uncollected.
• NCERT says to treat waste as a resource for energy and compost. Untreated waste rots slowly and releases methane (Fig. 9.3, Mahim).
• Legacy waste: old dumps at Ghazipur, Bhalswa and Okhla (Delhi) and Deonar (Mumbai). They release methane, catch fire and leak leachate (toxic liquid). SBM-Urban 2.0 (2021) aims to clear them by bio-mining.
• Solid Waste Management Rules 2026 (in force 1 April 2026, replacing the 2016 Rules):
• waste sorted into four streams: wet, dry, sanitary and special care
• landfill only for leftover waste

• environmental compensation charged to polluters (verify current)

• Single-use plastic ban: identified items banned from 1 July 2022. Carry bags must be at least 120 microns thick.

• Extended producer responsibility (EPR): producers, importers and brand owners must collect and recycle what they sell. It applies to plastic packaging, e-waste, batteries and tyres.
• E-waste: India is the third-largest generator after China and the US. The E-Waste Rules 2022 set recycling targets, but much e-waste is still handled informally, for example in Seelampur, Delhi (verify current).

8. Case study: Daurala and the polluter pays principle

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• Daurala case study:
• Where: a village near Meerut, UP, with about 12,000 residents.

• Problem: its groundwater had heavy metals in it, because untreated wastewater from Daurala's industries seeped down to the water table.

• Steps:

• In 2003, a Meerut-based NGO surveyed residents' health door to door.
• The NGO, villagers, people's representatives, officials and industry met and agreed on solutions.
• A bigger overhead tank and a 900 m extra pipeline brought safe drinking water.
• The village pond was desilted to recharge aquifers.
• Rainwater harvesting diluted the contaminants after the monsoon.

• 1,000 trees were planted.

• Result: improvement within about three years.

• Polluter pays principle: whoever causes pollution pays to prevent and clean it up.
• The Supreme Court made it part of Indian law in Indian Council for Enviro-Legal Action v. Union of India (1996), about the Bichhri village case in Rajasthan.
• It was applied again in Vellore Citizens' Welfare Forum (1996), about Tamil Nadu tanneries.

• It underpins NGT compensation and EPR.

• Lesson: scientific evidence, community pressure and industry participation together work.

9. Rural-urban migration and the informal sector

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• Rural-urban migration has three causes:
• high demand for labour in cities
• few jobs in villages

• uneven development between rural and urban areas

• Poor migrants often bypass small and medium towns and go straight to megacities.

• Urban growth comes from natural increase, net in-migration and reclassification of villages as towns. NCERT credits about 60% of urban growth after 1961 to natural increase and about 29% to rural-urban migration (the textbook sentence is garbled, so use with care).
• World: 55% of people live in cities now, rising to 68% by 2050 (UN, 2018).
• Ramesh case (Odisha):
• Push factors: debt, three acres shared by three brothers, school left after Class 9.
• Pull factors: successful migrants from his village.

• Journey: Ludhiana (woollen factory, ₹20 a day, 1988), then Surat (learnt welding), then contract work across Surat, Mumbai, Gandhinagar, Bharuch, Jamnagar and Talcher. He remits ₹20,000 a year.

• Informal sector: small unregistered firms and casual work with no job security or social protection. Most poor, unskilled migrants end up here on low wages.

• Consequences: wives stay home with children and elders, so the migration stream is male-dominated. Remittances raise living standards in the village, but families live apart.
• Beyond NCERT:
• Census 2011 counted about 45.6 crore migrants (by last residence). Most moved short distances and most were women moving for marriage.
• Long-distance work migration runs from UP, Bihar, Odisha and Jharkhand to Maharashtra, Delhi, Gujarat, Punjab and Kerala.
• The 2020 COVID exodus led to One Nation One Ration Card and the e-Shram portal (2021) (verify current).

10. Slums, Dharavi and the sanitation missions

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• Indian cities are sharply divided. High-income areas with wide roads and parks sit at one end. Slums, jhuggi-jhopri clusters and shanty colonies sit at the other.
• Slum: a home area of "least choice", lived in by migrants who cannot afford rent or land. Slums stand on degraded, unsafe sites.
• Living conditions: broken-down houses, poor ventilation, no drinking water, light or toilets, open defecation and crowded lanes.

• Effects on residents: low-paid, high-risk work, poor nutrition, disease, children out of school, and exposure to drug abuse, crime and social exclusion.

• Dharavi (Seabrook, 1996), described as Asia's largest slum:

• It lies in central Mumbai, on land reclaimed from an arm of the sea using waste.
• It has one "ninety-foot road" and lanes too narrow for a bicycle. A family of twelve may share one room.
• Yet it makes pottery, zari, leather goods, garments and metalwork, so it helps create Mumbai's wealth.

• Redevelopment was awarded in 2022 and faces rehousing disputes (verify current).

• Census 2011 slum data: about 6.5 crore slum dwellers in 2,613 towns, about one in six urban residents there.

• Three categories: notified, recognised and identified.

• Maharashtra has the most.

• Swachh Bharat Mission: launched on 2 October 2014, with urban and rural parts. NCERT links it to a better life in urban slums. Rural India was declared ODF (open-defecation free) on 2 October 2019.

• Swachh Bharat Mission (Grameen) Phase II (2020-21 to 2024-25): aims at ODF Plus, meaning toilets that stay in use, solid and liquid waste management, and visible cleanliness.
• Swachh Survekshan (an annual city cleanliness survey since 2016): Indore has been ranked cleanest every year since 2017. Top cities now compete in a separate Super Swachh League (verify current).

11. Land degradation and wastelands

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• Land degradation: a temporary or permanent fall in land's ability to produce. It is caused by soil erosion, waterlogging, salinisation (salt build-up), alkalinisation and constant use without restoring fertility.
• Wasteland: degraded land left unused or underused. Not all degraded land is wasteland, but unchecked degradation turns land into wasteland.
• NRSC's three classes, made using remote sensing (satellite images):

Cause	Types
Natural agents	Gullied and ravinous land (Chambal, Yamuna and Mahi valleys), desert and coastal sands, barren rocky areas, steep slopes, glacial areas
Natural + human	Waterlogged and marshy land, saline and alkaline land, land with or without scrub
Human action	Degraded shifting cultivation areas, plantations, forests and pastures; mining and industrial wastelands

• NCERT stresses that man-made wastelands matter more than natural ones.
• Wastelands Atlas of India (DoLR and NRSC, 2019): wastelands fell from 56.6 million ha (2008-09) to 55.8 million ha (2015-16), about 17% of India.
• Desertification and Land Degradation Atlas of India (ISRO-SAC, 2021): about 97.85 million ha, nearly 30% of India, was degraded in 2018-19. Water erosion is the main process. Rajasthan, Maharashtra and Gujarat have the largest areas (verify current).
• Land Degradation Neutrality (UNCCD; SDG 15.3): restore as much land as is degraded, so the total of healthy land stays stable.
• Bonn Challenge (2011): restore 150 million ha by 2020 and 350 million ha by 2030. At COP14 in Delhi (2019), India raised its target to 26 million ha by 2030.

12. Case study: the Jhabua watershed and community management of commons

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• Jhabua watershed case study:
• Where: Jhabua district, in Madhya Pradesh's westernmost agro-climatic zone. It was one of India's five most backward districts.
• Who: mostly Bhils, one of India's largest tribes, also found in Rajasthan, Gujarat and Maharashtra.

• Problem: degraded forests and land made their poverty worse.

• Watershed management treats land, water and plants of a drainage area together, with community participation.

• It was funded by the Ministries of Rural Development and Agriculture.
• It was run by the Rajiv Gandhi Mission for Watershed Management.

• It treated 20% of the district in five years.

• Petlawad block (northern Jhabua; Sat Rundi hamlet, Karravat village), a government-NGO partnership:

• Each household planted and cared for one tree on common land.
• Fodder grass was planted on the pastures.
• Social fencing: a village agreement to keep animals off regrowing land without physical fences, kept for at least two years.

• After that, cattle were fed in stalls instead of open grazing.

• Conflict resolution: villagers called the tehsildar to confirm their rights to the common land. They then made a villager from a nearby village, who had encroached on it, a member of their user group so he shared the benefits.

• Lesson: restoration lasts when the community owns it and benefits are shared. WDC-PMKSY and MGNREGA natural resource works continue this model (verify current).

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Exam angles

Prelims — high-yield facts and traps

• Ganga polluted stretches: downstream of Kanpur, downstream of Varanasi, Farakka. Yamuna: Delhi to the Chambal confluence, plus Mathura and Agra. The Yamuna's dilution is low because Haryana and UP take water for irrigation.
• Chronology: GAP 1985 → NGRBA 2009 → NMCG 2011 → Namami Gange (June 2014) → SBM (2 Oct 2014) → AQI (Apr 2015) → NCAP (Jan 2019) → CAQM 2021 → single-use plastic ban (1 Jul 2022) → SWM Rules 2026 (1 Apr 2026).
• The CPCB was created under the Water Act 1974, not the EPA 1986. Trap: "CPCB was set up under EPA 1986" — FALSE.
• AQI uses eight pollutants and six bands. GRAP has four stages. A non-attainment city fails NAAQS for PM10 or NO₂ for five years in a row (2011–15).
• PM2.5: NAAQS 60/40 vs WHO 2021 15/5 µg/m³.
• Acid rain is below pH 5.6. In cities, the first rain after summer has the lowest pH. Smog = smoke + fog.
• Noise limits run from industrial 75/70 down to silence zone 50/40 dB(A). Traffic is the biggest noise source.
• BOD for bathing water is 3 mg/l or less. CPCB 2022 found 311 stretches on 279 rivers.
• Daurala: near Meerut, heavy metals in groundwater, polluter pays, 2003. Jhabua: Bhils, Petlawad, social fencing, Rajiv Gandhi Mission. Do not swap these cases.
• Chambal ravines are a natural-agent wasteland. NCERT says man-made wastelands matter more.
• Wastelands Atlas (about 17% wasteland) vs Desertification Atlas (about 30% degraded). "30% of India is wasteland" — FALSE.
• LDN = SDG 15.3. Bonn Challenge: 150 Mha by 2020, 350 Mha by 2030. India's target: 26 Mha by 2030.

Mains — GS-I and GS-III themes

1. Describe the nature of water pollution in India. Assess river cleaning from GAP to Namami Gange, including the sewage treatment gap.
2. Why is north Indian air pollution an airshed problem? Cover the basin's geography, inversions, stubble burning, and NCAP, CAQM and GRAP.
3. Urban waste as a resource: segregation, legacy dumps, EPR, informal recyclers and the SWM Rules 2026.
4. Rural-urban migration and the informal sector: causes, consequences and the case for portable welfare.
5. Problems of slums: in-situ redevelopment vs relocation (Dharavi), and the role of SBM and PMAY-U.
6. Measures to reduce land degradation, and community watershed management as in Jhabua.
7. The polluter pays principle in India: case law, Daurala, and its limits in enforcement.

Current-affairs hooks

• Delhi winter AQI spikes, GRAP stage changes, stubble-fire counts and CAQM directions.
• Swachh Vayu Survekshan rankings and NCAP's PM10 progress.
• CPCB polluted-stretch updates, Yamuna foam, and Ganga water quality during Kumbh.
• Rollout of the SWM Rules 2026, plastic EPR compliance, landfill fires and bio-mining.
• Swachh Survekshan results and SBM-G ODF Plus milestones.
• Dharavi redevelopment disputes and e-Shram migrant welfare.
• New wasteland or desertification atlases and UNCCD COP decisions.