NCERT
Every NCERT book that matters for UPSC — open a book, then a chapter. Learn each chapter's concepts, then how UPSC tests them — with diagrams, flowcharts and the past questions to attempt.
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← India: Physical Environment — all chaptersNatural Hazards and Disasters: Causes, Consequences and Management
Start here: why this chapter matters
In simple wordsA heavy rainstorm over an empty field is just weather. The same storm over a crowded slum on a river bank is a disaster. This chapter is about that difference: which natural events threaten India, where, and what we can do so that hazards don't turn into disasters.
NCERT opens with change: some changes are slow (landforms evolving), some sudden (earthquakes, tsunamis); some local (hailstorms), some global (global warming). To nature they are neutral; to people some are good (seasons, ripening fruit) and some bad (earthquakes, floods, wars). Disasters are the feared kind. This last chapter of the book pulls together everything before it — the plate (Chapter 2), the rivers (Chapter 3), the monsoon (Chapter 4) and the forests (Chapter 5) — to explain India's hazards.
- Physical Geography links: earthquakes, waves and the 2004 tsunami (Chapter 3), plate movement (Chapter 4), mass movement and landslides (Chapter 5), cyclones (Chapter 9). This chapter adds India's zones and management.
- UPSC: Disaster management is a named topic in GS3; GS1 asks about floods, earthquakes and landslides; Prelims ask about causes, effects and institutions.
| Word | What it means here |
|---|---|
| Natural hazard | An element of the natural environment that could harm people or property — steep slopes, ocean currents, extreme climates |
| Disaster | A sudden event causing large-scale death, damage and disruption, needing help beyond normal emergency services |
| Vulnerability | How exposed and unable to cope people are — where they live, how they build, how poor they are |
| Mitigation | Steps that reduce the damage a hazard can do (codes, shelters, embankments, afforestation) |
| Preparedness | Being ready before the event — warnings, plans, drills, stockpiles |
| Storm surge | An abnormal rise of the sea pushed onto the coast by a cyclone |
| Flash flood | A sudden, short-lived flood from intense rain, often in dry areas |
| Liquefaction | Shaken, water-soaked soil behaving like a liquid in an earthquake |
Reading the Unit IV page (page 52)Unit IV — Natural Hazards and Disasters — lists four themes: floods and droughts; earthquakes and tsunami; cyclones; landslides. The chapter covers each, then management.
At a glance — the six ideas to carry away
- Hazard + vulnerability → disaster when losses exceed the community's coping capacity.
- Four families (Table 6.1): atmospheric · terrestrial · aquatic · biological.
- Earthquakes: five damage-risk zones; very high in the north-east, the Himalayan arc and Kachchh.
- Tsunami: low and long at sea, up to 15 m+ near the coast; cyclones: 30°N–30°S, none at 0°–5°.
- Floods: 40 million ha flood-prone; droughts: ≈ 30% of area drought-prone, extreme west of the Aravali.
- Management: pre-disaster · during · post-disaster; Yokohama 1994; Disaster Management law 2005.
1. Hazards, disasters and the human role
In simple wordsA loaded gun on a table is a hazard; someone standing in front of it is vulnerable; if it goes off, that's the disaster. You can't always remove the gun (nature), but you can move people out of the line of fire.
NCERT defines a disaster as an undesirable occurrence from forces largely outside human control, striking quickly with little warning, causing or threatening serious disruption of life and property, and needing efforts beyond normal statutory emergency services. Disasters are not only natural: some are directly human-made (the Bhopal gas tragedy, Chernobyl, wars, CFCs and greenhouse gases, pollution); others are indirectly worsened by people (landslides and floods from deforestation, unscientific land use and building in fragile areas).
- Hazards may be swift or permanent features of a place (currents, steep unstable Himalayan slopes, desert or glacial extremes); disasters are sudden, large-scale and hard to control.
- No two disasters are alike — each depends on local social and environmental conditions — but their magnitude, frequency and damage have increased, and so has concern.
- Earlier, people avoided intensive use of hazard-prone areas. Technology has let us push into them — colonising flood plains and building cities such as Mumbai and Chennai right up to the shore — raising vulnerability to cyclones and tsunamis.
Exam trapA hazard is not a disaster. A hazard becomes a disaster only when it meets vulnerable people and property and the damage is very high (exercise Q2-i). And many ‘natural’ disasters have a human hand in them.
2. Classifying disasters, and the world's response
In simple wordsSorting disasters is like sorting illnesses by the organ they affect: some come from the air, some from the ground, some from water, some from living things. Knowing the family helps decide who should respond and how.
Reading the Yokohama Strategy and IDNDR box (page 56)
- UN members met at the World Conference on Natural Disaster Reduction, Yokohama, 23–27 May 1994. It noted rising losses and that disasters hit the poor and developing countries hardest.
- Resolutions: each country is responsible for protecting its citizens; priority to developing, least developed, land-locked and small-island states; build national capacities and laws, with NGOs and local communities; promote regional and international cooperation — capacity-building, technology and information sharing, mobilising resources.
- It declared 1990–2000 the International Decade for Natural Disaster Reduction (IDNDR). The issue had first been raised at the UN General Assembly in 1989.
NCERT check — datesNCERT lists the ‘Earth Summit at Rio de Janeiro, Brazil, 1993’. The Rio Earth Summit (UN Conference on Environment and Development) was held in June 1992.
Beyond NCERT — after Yokohama (Mains 2018, 2024)
- The Hyogo Framework for Action (2005–2015) followed Yokohama; it was replaced by the Sendai Framework for Disaster Risk Reduction (2015–2030), adopted in Sendai, Japan, in March 2015, with seven global targets (fewer deaths and affected people, lower economic and infrastructure losses, more national and local strategies, more international cooperation, better access to early warning) and four priorities (understand risk, strengthen risk governance, invest in resilience, improve preparedness and ‘build back better’). The 2024 Mains question wrote ‘2020–2030’; the framework runs 2015–2030.
- The key shift: from managing disasters after they happen to reducing risk before they happen.
3. Earthquakes
In simple wordsPush two heavy tables against each other: they jam, the push builds up, and then one suddenly slips with a bang. India's plate is pushing into Asia's; along the Himalaya the jam keeps building and releasing — that is why the north and north-east shake so often.
Earthquakes are the most unpredictable and destructive of disasters. Tectonic earthquakes cause the most damage over the largest areas; those from volcanoes, rock falls, landslides, mine subsidence and reservoir impounding are more local. The Indian plate moves north and north-east and is obstructed by the Eurasian plate; the two are locked, energy builds up, and its sudden release causes earthquakes along the Himalayan arc. Most vulnerable: J&K, Ladakh, Himachal Pradesh, Uttarakhand, Sikkim, the Darjeeling subdivision and all seven north-eastern states.
The Peninsula too. Gujarat (1819, 1956, 2001) and Maharashtra (1967, 1993) have had severe earthquakes. Some scientists suggest a fault and energy build-up along the Bhima (Krishna) near Latur and Osmanabad, and a possible breaking of the Indian plate. Analysing over 1,200 past earthquakes, the National Geophysical Laboratory, the Geological Survey of India, the Meteorology Department and the National Institute of Disaster Management divided India into five zones.
Reading NCERT Figure 6.2 — Earthquake Hazard Zones (page 58)
- Five shades, each tagged with an MSK intensity: very high (IX), high (VIII), moderate (VII), low (VI), very low (V).
- Very high: the whole north-east, separate patches in Kashmir, Himachal and Uttarakhand, a patch on the Bihar–Nepal border, and Kachchh.
- High: a broad belt along the Himalayan foothills and plains in the north; a small patch on the west coast near 17°N (Beyond NCERT: the Koyna area of Maharashtra, where the 1967 earthquake was reservoir-induced).
- Very low: dotted blocks in Rajasthan–MP, interior Chhattisgarh–Odisha and the interior Karnataka–Andhra plateau, ringed by ‘low’ belts.
Reading NCERT Figure 6.1 and Table 6.2 (pages 55–57)
- Figure 6.1: a two-storey brick-and-plaster house with a wall and part of the upper floor torn open and collapsed — unreinforced masonry is what kills in earthquakes.
- Table 6.2 — Effects of earthquakes: on ground — fissures, settlements, landslides, liquefaction, earth pressure; on man-made structures — cracking, sliding, overturning, buckling, collapse; on water — waves, hydro-dynamic pressure, tsunami; each with possible chain effects.
- Consequences: worst where population is dense — settlements, transport, communications, industry destroyed; people made homeless; poorer economies hit hardest. Surface waves open fissures; landslides block rivers into lakes; rivers may change course and flood.
- Mitigation (prevention is impossible): (i) seismological centres and GPS monitoring of plate movement; (ii) a vulnerability map and public awareness; (iii) changing house types, discouraging high-rise buildings, large industries and big cities in vulnerable areas; (iv) mandatory earthquake-resistant designs and light materials.
NCERT check — plate speed and zone count
- NCERT says the Indian plate moves ‘one centimetre per year’. GPS measurements put India's motion relative to Eurasia at roughly 4–5 cm per year (Beyond NCERT).
- NCERT's five damage-risk zones (with MSK intensities) are not the same as the official seismic zones II–V of the Bureau of Indian Standards' building code. Quote ‘Zone V’ for the code; NCERT's names for this chapter.
Beyond NCERTThe dates in NCERT's list match well-known events: Koyna (1967) — reservoir-induced; Latur (1993); Bhuj (2001) — Kachchh. The 2005 earthquake in Kashmir (on both sides of the Line of Control) is the one NCERT's opening refers to.
4. Tsunami
In simple wordsFlick a long rope lying flat: the ripple is low as it runs, but if the far end is tied to a wall it suddenly jumps up. A tsunami does the same — a low, very long swell in deep water that piles up into a wall of water where the sea gets shallow.
Earthquakes or eruptions that move the sea floor abruptly displace the water, creating tsunamis (‘harbour waves’, seismic sea waves): one instantaneous vertical wave and then a series of after-waves. In deep water the wavelength is very long and the height small, so a ship rises only a metre or two over several minutes and the wave is hard to detect. Entering shallow water, the wavelength shortens while the period stays the same, so the height grows — 15 m or more. Tsunamis are common around the Pacific Ring of Fire — Alaska, Japan, the Philippines, Indonesia, Malaysia, Myanmar, Sri Lanka, India.
Reading NCERT Figure 6.3 — Tsunami Affected Area (page 59)A stranded boat lying on land among smashed timber, broken roofs and uprooted palms — the debris field a tsunami leaves when it surges inland and drains back.
- Coasts are densely populated and busy, so a tsunami usually kills more than other coastal hazards.
- Mitigation is beyond any single country — it needs international effort. India joined the International Tsunami Warning System after the 26 December 2004 tsunami.
NCERT check — the 2004 death tollThis chapter says ‘more than 300,000 people lost their lives’ in 2004; most official estimates are about 2.3 lakh across 14 countries (the live Physical Geography Chapter 3 page uses ‘over 2 lakh’). Use ‘over two lakh in 14 countries’. Beyond NCERT: India's Indian Tsunami Early Warning Centre at INCOIS, Hyderabad, has run since 2007.
5. Tropical cyclones
In simple wordsA tropical cyclone is a steam engine made of weather: warm sea water evaporates, the vapour condenses into cloud, and the heat released drives the winds faster. Cut off the fuel — move it over land — and it weakens. That is why the coast takes the worst of it.
Tropical cyclones are intense lows between 30°N and 30°S, 500–1,000 km across and from the surface up to 12–14 km, powered by latent heat of condensation. Initial conditions (NCERT): (i) a large, continuous supply of warm, moist air; (ii) a strong Coriolis force to stop the low from filling — so none form at 0°–5°; (iii) unstable conditions through the troposphere; (iv) no strong vertical wind shear (NCERT prints ‘wind wedge’), which would disrupt the vertical transport of heat.
- India's cyclones come from the Bay of Bengal and the Arabian Sea. Most form at 10°–15°N in the monsoon season; in the Bay of Bengal, mostly in October–November, from about 16°N and west of 92°E; by July the genesis area shifts to about 18°N, west of 90°E, near the Sunderbans.
- Force falls with distance from the sea; coasts get severe storms with average speeds of 180 km/h and an abnormal rise in sea level — the storm surge, which floods settlements and fields.
⤵ How a cyclone becomes a coastal disaster
Intense low over a warm sealatent heat keeps feeding it
Very strong winds≈ 180 km/h average at the coast; steep pressure gradient
Storm surge + torrential rainsea pushed onto the land; rivers swell
Coastal floodingsettlements, fields and deltas inundated
With warning and evacuationcyclone shelters, embankments, afforestation → losses limited
Without themcrowded, low coasts → heavy loss of life and property
Reading NCERT Figure 6.4 — Wind and Cyclone Hazard Zones (page 61)
- Six classes by a design wind speed V: very high A (55 m/s), very high B (50 m/s), high (47 m/s), moderate A (44 m/s), moderate B (39 m/s), low (34 m/s) — numbers given only in the figure.
- The very high B belt hugs the whole east coast, the Gujarat coast and the Brahmaputra valley; very high A covers Ladakh and the Mizoram–Tripura area. The Ganga plain and the north-west are ‘high’; the interior Karnataka plateau is the ‘low’ zone.
- The map mixes cyclone risk with general wind risk — that is why inland Ladakh appears in the top class.
Beyond NCERT (asked by UPSC)The India Meteorological Department issues colour-coded warnings — green, yellow, orange, red — rising with the expected severity and the action needed (Mains 2022). The Odisha super cyclone (1999) and the Gujarat cyclone (1998) are the events behind NCERT's project topic; Odisha's later success in mass evacuation (e.g. Phailin, 2013) is a standard example of preparedness.
6. Floods
In simple wordsA river channel is a pipe. Pour in more water than the pipe can carry — or block the pipe — and it overflows onto the land around. Most Indian floods are this simple; what makes them disasters is that millions of people live right where the pipe overflows.
Flooding happens when surface run-off exceeds the carrying capacity of channels and spills onto flood plains. Causes: storm surges, long spells of intense rain, melting ice and snow, lower infiltration, and silt from soil erosion. Unlike other disasters, floods are well understood, slow, and seasonal in known places — and people play a big role: deforestation, unscientific farming, disturbing natural drainage and settling flood plains and river beds.
Reading NCERT Figure 6.6 — Flood Hazard Zones (page 63)
- One shade — ‘area liable to flood’ — laid over the river network.
- Long shaded ribbons follow the Ganga, Yamuna, Ghaghara, Gandak and Kosi across UP and Bihar, the Brahmaputra valley in Assam, and the Bengal delta.
- Other patches: a block in Punjab–Haryana, the mouths of the Sabarmati, Mahi and Narmada in Gujarat, and the Mahanadi, Godavari and Krishna deltas. Most of the Peninsula is unshaded.
Reading NCERT Figure 6.5 — Brahmaputra During Flood (page 62)A wooded island nearly surrounded by a vast, still sheet of water stretching to distant hills — the river spread far beyond its channel, as it does every monsoon around islands such as Majuli, the largest river island in the world (NCERT).
- Consequences: crops, roads, rails, bridges and homes destroyed; millions homeless; cattle lost; cholera, gastro-enteritis, hepatitis and other water-borne diseases. Benefit: fresh silt — Majuli's good paddy after floods — small next to the losses.
- Control: embankments, dams, afforestation, no major construction in upper catchments; removing encroachments from channels and depopulating flood plains (especially for flash floods in the west and north); cyclone centres for surge-hit coasts.
Exam traps
- Floods in Tamil Nadu come in November–January from the retreating monsoon (exercise Q1-iii).
- The Indo-Gangetic plain floods because of heavy monsoon rain, huge silt loads and very gentle slopes — its porous alluvium is true but is not the reason (UPSC 1990 A–R).
- The main health hazard after floods is cholera and other water-borne disease (UPSC 1982).
Beyond NCERT (Mains 2016, 2020, 2024)Urban floods are a newer problem: building over lakes, wetlands and natural drains, concrete surfaces that stop infiltration, choked storm drains and very intense short bursts of rain. Examples often cited: Mumbai 2005, Chennai 2015, Hyderabad 2020. NCERT's own ideas — remove encroachments, restore drainage — apply directly.
7. Droughts
In simple wordsA flood arrives in a day; a drought creeps up over months. First the rain fails, then the soil dries, then wells and ponds run low, then whole ecosystems suffer — a slow disaster that hits the poorest hardest.
A drought is an extended shortage of water from inadequate rain, high evaporation and over-use of reservoirs and groundwater. It involves rainfall, evaporation, soil moisture, storage and run-off, but also crops grown, socio-economic practices and ecology.
⤵ From rainfall deficit to human crisis
Meteorological droughtrain fails or is badly distributed
Agricultural droughtsoil moisture drops → crops fail (akal, trinkal)
Hydrological droughtwells, lakes, reservoirs and aquifers run low (jalkal)
Ecological droughtecosystem productivity fails; cattle die, people migrate, disease spreads
Immediate reliefsafe drinking water, medicines, fodder, shifting people and livestock
Long-term mitigationgroundwater mapping, river linking, reservoirs, drought-resistant crops, rainwater harvesting
Reading NCERT Figure 6.7 — Drought Prone Areas (page 65)
- Four shades: Zone 1 extreme, Zone 2 severe, Zone 3 moderate, and drought-free.
- Extreme covers western Rajasthan and a strip of Kachchh. Severe covers a block from eastern Rajasthan through Madhya Pradesh, a separate north–south strip down the interior Deccan (rain shadow of the Western Ghats), and a patch in southern Jharkhand–interior Odisha.
- Moderate surrounds them (Gujarat, Maharashtra except Konkan, northern Rajasthan–Haryana, southern UP) with an isolated patch on the Coimbatore plateau.
- The whole north-east, the Himalaya, the Ganga delta, the west coast and the east coast are drought-free — compare with the annual rainfall map in Chapter 4.
Reading NCERT Figure 6.8 — Drought (page 66)Bare, stony, cracked ground under a pale sky, with the skeleton of an animal in the foreground — the cattle deaths NCERT lists among drought's first consequences.
- Immediate steps: safe drinking water, medicines, fodder and water for cattle, shifting people and livestock to safer places.
- Long-term: map groundwater (aquifers), transfer water from surplus to deficit areas, inter-link rivers, build reservoirs; use remote sensing to find linkable basins and groundwater; spread drought-resistant crops; rainwater harvesting.
NCERT check — inconsistent drought numbersNCERT says 12% of the population suffers drought every year, but also that the drought-prone 30% of the area affects ‘around 50 million people’. Twelve per cent of India's population is far more than 50 million. Quote the area figures (19% each year, 30% drought-prone) and treat the population figures with care.
Exam trapMore droughts in central and western India (exercise Q2-v) because rainfall there is low and highly variable, the area lies in the rain shadow or far from the monsoon branches, evaporation is high and irrigation limited — not because of western disturbances. Successive monsoon failure caused Gujarat's four-year drought (UPSC 1988).
8. Landslides
In simple wordsA steep pile of wet sand on a slope stays put — until you dig at its foot or pour on more water, and then it slumps. Hill roads cut into slopes, heavy rain soaks them, earthquakes shake them: the mountains slide.
A landslide is the rapid sliding of a large mass of bedrock and debris. Less dramatic than earthquakes or cyclones, landslides still hurt the environment and economy badly — blocked roads to Srinagar, rock falls on the Konkan Railway. They are controlled by very local factors (geology, geomorphic agents, slope, land use, vegetation, human activity), so monitoring is hard and costly.
Reading NCERT Figure 6.9 — Landslide (page 67)A steep hillside scarred by a broad, fan-shaped tongue of loose grey debris with long downslope streaks — fresh slide material spread over the slope.
- Consequences: small direct area, but road blocks, broken rail lines and blocked channels have far-reaching effects; diverted rivers can flood; movement becomes risky and costly, holding back development.
- Mitigation (area-specific): restrict roads, dams and big settlements in high-risk zones; keep farming to valleys and moderate slopes; large-scale afforestation; bunds to slow run-off; terrace farming in north-eastern hill states where jhumming (slash-and-burn) is practised.
Beyond NCERTThe Malpa landslide (exercise Q1-ii) struck in August 1998 in the Pithoragarh district of Uttarakhand (then Uttar Pradesh; NCERT still says ‘Uttaranchal’), killing over 200 people, including Kailash–Mansarovar pilgrims. NDMA has issued landslide guidelines and a National Landslide Risk Management Strategy (Mains 2021).
9. Disaster management
In simple wordsFire safety in a school is not just the fire brigade: it is fire drills before, quick evacuation during, and repairing and learning after. Disaster management works the same way, at the scale of a country.
Cyclones are more predictable in time and place than earthquakes, tsunamis or eruptions, so they can be managed better — cyclone shelters, embankments, dykes, reservoirs, wind-breaking afforestation. Yet losses keep rising in India, Bangladesh and Myanmar because so many vulnerable people live on the coasts.
Reading the ‘Disaster Management Bill, 2005’ box (page 68)It defines a disaster as a catastrophe, mishap, calamity or grave occurrence in any area, from natural or man-made causes, or by accident or negligence, causing substantial loss of life, human suffering, or damage to property or the environment, of such a nature or magnitude as to be beyond the coping capacity of the affected community. NCERT names it, together with the National Institute of Disaster Management, as positive steps by the Government of India.
Beyond NCERT — India's disaster-management system
- The Bill became the Disaster Management Act, 2005. It set up the National Disaster Management Authority (NDMA), chaired by the Prime Minister; State authorities chaired by the Chief Ministers; District authorities headed by the District Collector/Magistrate; the National Disaster Response Force (NDRF); and made the NIDM a statutory institute.
- The shift since 2005 has been from relief after the event to prevention, mitigation and preparedness (Mains 2020), guided since 2015 by the Sendai Framework.
- NDMA guidelines exist for individual hazards — for example drought (2010) and cloudbursts and landslides — which UPSC Mains has asked about (2014, 2016).
⤵ From hazard to resilience
Know the hazardmonitoring, zoning maps (Figures 6.2, 6.4, 6.6, 6.7)
Reduce vulnerabilitybuilding codes, land-use control, embankments, afforestation
Preparewarnings, shelters, drills, community awareness
Respondrescue, relief, health care
Recover and build back betterrehabilitation, capacity-building
Development can cause disasters (exercise Q3-iii)Development becomes a cause of disaster when it ignores hazard zones: roads and dams cut into unstable Himalayan slopes; cities built over flood plains, lakes and drains; deforestation in catchments; mining causing subsidence; reservoirs triggering earthquakes; coastal construction removing mangroves. UPSC 2026 Mains asked how to reconcile rapid infrastructure with disaster-risk reduction in ecologically sensitive areas.
NCERT's in-text questions — short answers
List changes that take a long time and changes that are quick; why are some good and others bad?
Slow: landform evolution, soil formation, climate change. Quick: earthquakes, floods, storms. ‘Good’ or ‘bad’ is a human judgement — changes that help us (seasons, ripening crops) are welcomed; those that harm life and property are feared.
Identify human activities in your neighbourhood that could lead to disasters, and suggest prevention.
Building on drains or slopes, dumping in channels, cutting trees, unsafe high-rises, encroaching on lakes. Prevention: enforce building codes and zoning, keep drains clear, plant trees, harvest rainwater, protect wetlands.
How do governments generally respond to floods?
Embankments, dams, afforestation, controlling construction in upper catchments, removing encroachments and depopulating flood plains, relief camps and cyclone centres (NCERT's list).
Observe roof-top rainwater harvesting in your locality and suggest improvements.
Clean roofs and gutters, add first-flush diverters and filters, connect to recharge pits or tanks, maintain them before the monsoon, and make it mandatory for new buildings.
NCERT exercise — answer outlines
Try each question yourself first, then open the outline to compare.
1(i) Which one of the following states of India experiences floods frequently? (a) Bihar (b) West Bengal (c) Assam (d) Uttar Pradesh
Usual answer: (c) Assam. But NCERT names Assam, West Bengal and Bihar together as highly flood-prone, so (a) and (b) are also defensible; in an exam choose Assam as the most frequent (Brahmaputra floods every year). Kept out of the self-check because of this ambiguity.
1(ii) In which district of Uttaranchal did the Malpa landslide take place? (a) Bageshwar (b) Champawat (c) Almora (d) Pithoragarh
(d) Pithoragarh (August 1998; Beyond the text).
1(iii) Which state receives floods in the winter months? (a) Assam (b) West Bengal (c) Kerala (d) Tamil Nadu
(d) Tamil Nadu — November–January, from the retreating monsoon.
1(iv) In which river is Majuli River Island situated? (a) Ganga (b) Brahmaputra (c) Godavari (d) Indus
(b) Brahmaputra.
1(v) Under which type of natural hazards do blizzards come? (a) Atmospheric (b) Aquatic (c) Terrestrial (d) Biological
(a) Atmospheric (Table 6.1).
2(i) When can a hazard become a disaster? (30 words)
When a hazard strikes vulnerable people and property and the damage is so large that it disrupts life and is beyond the community's capacity to cope — e.g. a cyclone hitting a crowded low coast.
2(ii) Why are there more earthquakes in the Himalayas and the north-east? (30 words)
The Indian plate pushes north/north-east into the Eurasian plate; the plates are locked, stress builds up and is released suddenly along the young, still-rising Himalayan arc and the north-eastern ranges.
2(iii) What are the basic requirements for the formation of a cyclone? (30 words)
Large, continuous supply of warm, moist air (warm seas); strong Coriolis force (so not within 0°–5°); unstable troposphere with a pre-existing disturbance; absence of strong vertical wind shear.
2(iv) How are floods in eastern India different from those in western India? (30 words)
East (Assam, West Bengal, Bihar, eastern UP): large perennial rivers, heavy rain, silt — recurrent, long, widespread river floods. West (Punjab, Rajasthan, N Gujarat, Haryana): sudden, short flash floods from intense rain and blocked streams.
2(v) Why are there more droughts in central and western India? (30 words)
Low, highly variable rainfall; rain-shadow and distance from the monsoon branches; high evaporation; sandy soils; limited irrigation and over-use of groundwater.
3(i) Identify the landslide-prone regions of India and suggest mitigation. (125 words)
Very high: young Himalaya, Andaman & Nicobar, rainy steep Western Ghats and Nilgiris, the north-east, quake-prone and heavily built-up hill areas. High: all Himalayan and north-eastern states except the Assam plains. Moderate–low: Trans-Himalaya, Aravali, rain-shadow Ghats and Deccan, mining areas. Safe: plains and southern coasts.
Mitigation: hazard-zonation maps; restrict roads, dams and settlements in high-risk zones; farm valleys and gentle slopes; afforestation; bunds and drainage; terracing instead of jhum; slope engineering and early warning (Beyond NCERT). A zone sketch helps.
Mitigation: hazard-zonation maps; restrict roads, dams and settlements in high-risk zones; farm valleys and gentle slopes; afforestation; bunds and drainage; terracing instead of jhum; slope engineering and early warning (Beyond NCERT). A zone sketch helps.
3(ii) What is vulnerability? Divide India into drought vulnerability zones and suggest mitigation. (125 words)
Vulnerability: the degree to which people, property and systems are exposed and unable to cope with a hazard.
Zones: extreme — west of the Aravali, Kachchh (Jaisalmer, Barmer under 90 mm); severe — eastern Rajasthan, most of MP, eastern Maharashtra, interior AP and Karnataka, northern interior TN, southern Jharkhand, interior Odisha; moderate — northern Rajasthan, Haryana, southern UP, rest of Gujarat, Maharashtra except Konkan, Coimbatore plateau, interior Karnataka; rest less prone.
Mitigation: drinking water, fodder, medicine and relocation now; groundwater mapping, river linking, reservoirs, remote sensing, drought-resistant crops and rainwater harvesting later.
Zones: extreme — west of the Aravali, Kachchh (Jaisalmer, Barmer under 90 mm); severe — eastern Rajasthan, most of MP, eastern Maharashtra, interior AP and Karnataka, northern interior TN, southern Jharkhand, interior Odisha; moderate — northern Rajasthan, Haryana, southern UP, rest of Gujarat, Maharashtra except Konkan, Coimbatore plateau, interior Karnataka; rest less prone.
Mitigation: drinking water, fodder, medicine and relocation now; groundwater mapping, river linking, reservoirs, remote sensing, drought-resistant crops and rainwater harvesting later.
3(iii) When can developmental activities become the cause of disasters? (125 words)
When they ignore hazards: roads, tunnels and dams in fragile Himalayan slopes (landslides, flash floods); cities on flood plains, lakes and drains (urban floods); deforestation and unscientific farming (floods, soil erosion); large reservoirs (induced earthquakes, e.g. Koyna — Beyond NCERT); mining (subsidence); coastal building and mangrove loss (surge, erosion); industrial negligence (Bhopal). Way out: hazard zoning, environmental impact assessment, building codes, ‘build back better’.
Project: prepare a report on one of — Malpa landslide, tsunami, Odisha and Gujarat cyclones, inter-linking of rivers, Tehri/Sardar Sarovar, Bhuj/Latur earthquakes, life in a delta or river island, a rooftop rainwater-harvesting model.
Structure each report: what happened / what it is (date, place, scale) → physical causes (link to the right chapter) → human factors and vulnerability → impacts → response and lessons (pre-, during, post-disaster) → your recommendations. Use official sources (IMD, NDMA, GSI) and one labelled sketch.
What to remember
Numbers
Yokohama conference23–27 May 1994
IDNDR1990–2000
UN General Assembly takes up disasters1989
Earthquakes analysed for zoningmore than 1,200
Earthquake damage-risk zones (NCERT)5 (MSK V–IX)
Severe Peninsular quakesGujarat 1819, 1956, 2001 · Maharashtra 1967, 1993
Tsunami height at the coastup to 15 m or more
Cyclone belt30°N–30°S; none at 0°–5°
Cyclone size500–1,000 km across; 12–14 km high
Genesis10°–15°N (monsoon season); Bay Oct–Nov from ≈ 16°N, W of 92°E; July ≈ 18°N, W of 90°E
Average coastal cyclone wind180 km/h
Flood-prone area (Rashtriya Barh Ayog)40 million ha
Drought every year≈ 19% of area, 12% of population
Drought-prone area≈ 30% of area
Irrigation exemptionover 30% of gross cropped area irrigated → not drought-prone
Jaisalmer, Barmer rainfallunder 90 mm a year
India's vulnerable shareabout two-thirds of area and population
One-liners
- Hazard + vulnerability → disaster.
- Table 6.1: atmospheric, terrestrial, aquatic, biological.
- Very high earthquake risk: north-east, Himalayan patches, N Bihar border, Kachchh.
- Tsunami: long and low at sea, tall at the coast — ‘shallow-water waves’.
- No cyclones at 0°–5°: too little Coriolis force.
- Flood types: river (east), cyclone (coasts), flash (west), winter (Tamil Nadu).
- Drought chain: meteorological → agricultural → hydrological → ecological.
- Management: before, during, after.
Traps to avoid
- A hazard is not a disaster until it meets vulnerability.
- Blizzards and drought are atmospheric in Table 6.1.
- Tamil Nadu floods in November–January.
- Rio Earth Summit was 1992, not 1993.
- The 2004 tsunami killed about 2.3 lakh, not 3 lakh.
- Indian plate moves about 4–5 cm/yr, not 1 cm.
- NCERT's five damage zones ≠ the BIS code's zones II–V.
- ‘Wind wedge’ in NCERT means vertical wind shear.
- Sendai Framework runs 2015–2030 (one UPSC question printed 2020–2030).
How to strategise
Prelims — what UPSC asks
- Prelims has asked surprisingly little directly from this chapter: health after floods — cholera (1982 ×2), deforestation and floods (1979), Indo-Gangetic floods A–R (1990), Gujarat's drought from monsoon failure (1988), silting and floods (2000).
- Expect statement questions on institutions (NDMA chaired by the PM, NDRF, Sendai's targets), on which disaster family a hazard belongs to, and on hazard regions (Kachchh in the highest earthquake class; Tamil Nadu's winter floods; Malpa in Pithoragarh).
- Earthquake waves, the Richter scale and tsunami mechanics are covered on the live Physical Geography Chapter 3 page; cyclone formation on Chapter 9; landslide processes on Chapter 5.
Mains — where it appears and how to answer
- GS3 disaster management is a regular source: vulnerability and risk assessment (2013), drought guidelines (2014), earthquake preparedness (2015), cloudbursts and urban floods (2016), the 2004 tsunami and NDMA guidelines (2017), Sendai vs Hyogo (2018), vulnerability and hazard zonation (2019), the shift from a reactive approach (2020), earthquake vulnerability and landslide strategy (2021), urban floods and resilience (2024), infrastructure vs risk reduction and community participation (2026).
- GS1: city floods (2016, 2020), Himalayan landslides (2016), IMD colour-coded cyclone warnings (2022), coastal hazard preparedness (2023).
- Answer frame: define (hazard, vulnerability, disaster) → India's exposure (zone with NCERT's regions) → causes, natural and human → impacts → management in three stages with institutions (DM Act 2005, NDMA, NDRF, Sendai) → a recent example → way forward (community participation, building back better).
Self-check
Tap an option. NCERT's own exercise questions come first; the rest test the figures and common confusions.
1. In which district did the Malpa landslide take place?
2. Which one of the following states receives floods in the winter months?
3. In which river is Majuli River Island situated?
4. Under which type of natural hazards do blizzards come?
5. Why does a tsunami barely lift a ship in deep water but rise to 15 m at the coast?
6. Why do tropical cyclones not form between 0° and 5° latitude?
7. An area is excluded from the drought-prone category, according to NCERT, if…
UPSC questions from this chapter
Open any question to attempt it in the Question bank — your attempt is saved to your progress.