Natural Hazards and Disasters

Why this chapter matters for UPSC: In the current rationalised NCERT (2026-27 reprint), this is Chapter 6 of India: Physical Environment (Unit IV, pp. 53-69) and the book's last chapter. It was Chapter 7 before Soils was dropped, and this site keeps the old number. It is the one NCERT chapter that covers the GS3 syllabus item "Disaster and disaster management" directly, and it supplies the hazard geography that GS1 questions on earthquakes, cyclones, floods and landslides rely on.

Contemporary hook: Two changes since the NCERT text was written affect exam answers. First, the Disaster Management (Amendment) Act, 2025 (assent 29 March 2025) amended the 2005 Act. Second, the Bureau of Indian Standards notified a new seismic code with a sixth zone in November 2025 and withdrew it on 3 March 2026, so India's earthquake zoning is again the four-zone map of IS 1893 (Part 1):2016. Both are covered below.

🧠 First Principles — Read This First

A natural hazard is something in the environment that can harm people or property. NCERT's examples are ocean currents, steep and unstable Himalayan slopes, and extreme conditions in deserts or glaciated areas. A disaster is what happens when such an event causes large-scale, sudden loss of life and property and disrupts society beyond its normal ability to cope.

The two are linked by vulnerability, meaning how exposed and how unprepared people are. A cyclone over an empty sea is only a hazard. The same cyclone striking a crowded, unprepared coast becomes a disaster. NCERT makes this point when it notes that people now settle floodplains and build port cities right up to the shore, which raises their vulnerability.

This leads to a second idea. Most natural hazards cannot be prevented: no one can stop an earthquake or a monsoon flood. What can be reduced is the harm they cause. Building codes, early warning, evacuation, land-use control and trained response forces all work on vulnerability rather than on the hazard. NCERT therefore concludes that "the next best option is mitigation and preparedness", organised as action before, during and after a disaster.

A useful comparison is a seat belt. It does not prevent accidents, but it decides whether a crash is survivable.

UPSC asks about this chapter as hazard geography in GS1 (why landslides are more frequent in the Himalaya, why cyclones form where they do) and as policy and institutions in GS3 (vulnerability, the DM Act, Sendai, preparedness).

PART 1 — Quick Reference

Table 1: NCERT classification of natural disasters

Source: NCERT IPE (2026-27), Ch. 6, Table 6.1. Drought appears in the atmospheric column and floods in the aquatic column. NCERT's own exercise places blizzards under "atmospheric".

Table 2: NCERT earthquake damage-risk zones

Source: NCERT IPE (2026-27), Ch. 6. The zoning came from analysis of more than 1,200 past earthquakes by the National Geophysical Laboratory, the Geological Survey of India, the Department of Meteorology and the National Institute of Disaster Management. NCERT's five "damage risk zones" are a different classification from the BIS engineering zones in Table 3.

Table 3: BIS seismic zoning (IS 1893, Part 1): status as of 1 October 2026

Sources: BIS "Know your standards" record for IS 1893 (Part 1):2025, which lists the standard as "(Withdrawn)" (accessed 1 Oct 2026). Withdrawal date and context: C. P. Rajendran, ETV Bharat, 11 Mar 2026 and The Economic Times (7 Mar 2026). The 2002 merger of Zone I and the Killari zone history are from NICEE, IIT Kanpur ("NICEE Remembers the 1993 Latur Earthquake"). The BIS record lists no superseding standard for the 2025 revision.

Table 4: India's disaster vulnerability: official figures

Source for NPDM figures: National Policy on Disaster Management 2009, PreventionWeb summary.

Table 5: Types of drought (NCERT) and the IMD definition

IMD's operational rule (beyond NCERT): A meteorological drought is declared when seasonal rainfall over an area is below 75% of its long-period average. It is moderate when the deficit is 26-50% and severe when the deficit is more than 50%. Sources: GIDM (Gujarat govt) drought training note quoting IMD; Business Standard, 10 Jul 2026, on IMD classification. Some sources list "socio-economic drought" as a fifth type. NCERT does not.

Table 6: Landslide vulnerability zones (NCERT)

Source: NCERT IPE (2026-27), Ch. 6.

PART 2 — Concepts & Narrative

From "acts of nature" to vulnerability

NCERT starts from a definition of disaster as "an undesirable occurrence resulting from forces that are largely outside human control, strikes quickly with little or no warning, which causes or threatens serious disruption of life and property … and requires therefore, mobilisation of efforts in excess of that which are normally provided by statutory emergency services."

It then describes three changes in thinking:

• Human causes. Disasters are not caused by natural forces alone. Some are directly human-made: the Bhopal gas tragedy, the Chernobyl nuclear disaster, wars, CFC release and greenhouse gases, and pollution. Others are made worse by human action, such as landslides and floods that follow deforestation and unscientific land use.
• Rising vulnerability. People once avoided intensive use of hazard-prone areas. Technology now lets them settle floodplains and build up to the shore, which raises their vulnerability.
• Scale beyond one country. Disasters can exceed what a single nation can handle. The UN General Assembly took up the issue in 1989. The World Conference on Natural Disaster Reduction at Yokohama (23-27 May 1994) adopted the Yokohama Strategy and Plan of Action for a Safer World. NCERT also notes that the decade 1990-2000 was declared the International Decade for Natural Disaster Reduction (IDNDR).

Earthquakes

NCERT calls earthquakes "by far the most unpredictable and highly destructive of all the natural disasters". Tectonic earthquakes cause the widest damage. Earthquakes linked to volcanoes, rock falls, landslides, mining subsidence or the filling of dams and reservoirs affect smaller areas.

Why the Himalaya shakes. NCERT says the Indian plate moves north and north-east at about 1 cm a year and is blocked by the Eurasian plate. The two plates are locked, energy builds up, and when the lock breaks the release causes earthquakes along the Himalayan arc. The most vulnerable areas NCERT lists are Jammu and Kashmir, Ladakh, Himachal Pradesh, Uttarakhand, Sikkim, the Darjeeling subdivision and all seven north-eastern states. (The 1 cm/yr figure is NCERT's. Rates measured by modern geodesy differ, so use the NCERT figure in an NCERT-based answer.)

Earthquakes in the "stable" Peninsula. NCERT names severe earthquakes in Gujarat (1819, 1956, 2001) and Maharashtra (1967, 1993). For the 1993 Latur event, it reports a theory of a fault line along the Bhima (Krishna) near Latur and Osmanabad, and a possible breaking of the Indian plate. The Killari (Latur) earthquake of September 1993 (magnitude about 6.2-6.4 in different catalogues) killed more than 8,000 people, according to NICEE (IIT Kanpur). At the time the area was mapped as Zone I, the lowest. The 2002 revision of IS 1893 merged Zone I into Zone II and put Killari in Zone III (Table 3).

Effects (NCERT Table 6.2).

• On the ground: fissures, settlements, landslides, liquefaction, earth pressure.
• On structures: cracking, sliding, overturning, buckling, collapse.
• On water: waves, hydrodynamic pressure, tsunami.

Each of these can set off further effects in a chain. Landslides caused by earthquakes can block rivers and create reservoirs, and rivers can change course and flood.

Mitigation (NCERT). NCERT says earthquakes cannot be prevented, so the emphasis should be on preparedness and mitigation rather than cure:

1. Seismological monitoring centres, and GPS to track plate movement.
2. A national vulnerability map, with risk information shared with people.
3. Changes to house types and building design in vulnerable areas, and discouraging high-rise buildings, large industries and big cities there.
4. Mandatory earthquake-resistant design and light materials for major construction.

Tropical cyclones

NCERT defines tropical cyclones as intense low-pressure areas between 30°N and 30°S, 500-1,000 km across and extending from the surface to 12-14 km high. They are heat engines, driven by the latent heat released when moisture picked up over the sea condenses. NCERT gives four initial conditions:

1. A large, continuous supply of warm, moist air that can release a great deal of latent heat.
2. A strong Coriolis force to stop the low pressure at the centre from filling. Because the Coriolis force is absent near the equator, cyclones do not form between 0° and 5° latitude.
3. Instability through the troposphere, which creates local disturbances around which a cyclone develops.
4. No strong vertical wind shear, which would disrupt the vertical transport of latent heat.

Where and when in India. NCERT says most cyclones form between 10° and 15°N in the monsoon season. In the Bay of Bengal they develop mostly in October and November, between 16° and 21°N and west of 92°E. By July the place of origin shifts to about 18°N, west of 90°E, near the Sundarbans delta. Cyclones weaken with distance from the sea. Coastal areas are struck by severe cyclonic storms with an average velocity of 180 km/h (NCERT), and these often raise the sea level abnormally, which is called storm surge. A surge forms from the interaction of air, sea and land, and floods settlements and fields. NCERT treats cyclones as more predictable than earthquakes or tsunamis. Shelters, embankments, dykes, reservoirs and afforestation reduce damage. NCERT attributes the losses in India, Bangladesh and Myanmar mainly to the high vulnerability of coastal populations.

Floods

NCERT notes that the causes of floods, unlike those of other disasters, are well established. Floods are relatively slow and occur in known regions at expected times of the year. They happen when run-off is more than river channels can carry. Other causes are storm surge, long spells of intense rain, melting snow and ice, reduced infiltration, and eroded sediment in the water. Human actions intensify floods: deforestation, unscientific farming, disturbing natural drainage channels, and settling floodplains and riverbeds.

Where.

• The Rashtriya Barh Ayog (National Flood Commission) identified 40 million ha as flood-prone.
• Assam, West Bengal and Bihar are among the high flood-prone states. Rivers in Punjab and Uttar Pradesh flood occasionally.
• Rajasthan, Gujarat, Haryana and Punjab have seen flash floods in recent decades. NCERT attributes this partly to the monsoon pattern and partly to human blocking of streams.
• Tamil Nadu sometimes floods in November-January from the retreating monsoon. This answers NCERT's exercise question on which state "receives floods in the winter months".

NCERT groups the regions by cause: flooding rivers in Assam, West Bengal, Bihar and eastern UP; cyclones on the coasts of Odisha, AP, TN and Gujarat; flash floods in Punjab, Rajasthan, northern Gujarat and Haryana.

Consequences and control. Floods destroy crops, roads, railways, bridges and homes, and spread cholera, gastro-enteritis and hepatitis. They also leave fertile silt. NCERT's example is Majuli in the Brahmaputra, "the largest riverine island in the world", which grows good paddy after the annual floods. NCERT calls these benefits "insignificant" compared with the losses. The control measures it lists are embankments, dams, afforestation, discouraging construction in the upper reaches, removing encroachments from channels, depopulating floodplains (especially where flash floods occur), and cyclone centres for coasts hit by storm surge.

Urban floods. NCERT does not treat urban flooding separately. The Mains banks have three questions on it: gs1-pyq-2016-17, gs1-pyq-2020-15 and gs3-pyq-2016-55, plus gs3-pyq-2024-18, which calls it "an emerging climate-induced disaster". Answers can use NCERT's points on blocked drainage and the settlement of floodplains and coasts.

Droughts

NCERT defines drought as an extended shortage of water caused by inadequate rain, high evaporation and over-use of reservoirs and groundwater. It involves meteorology, soil moisture, crops and social practice together. It also notes that floods and droughts are "the two accompanying features of Indian climate": one region can flood while another is in drought, and the same region can face both in different seasons because the monsoon is so variable.

Drought regions by severity (NCERT).

• Extreme: most of Rajasthan west of the Aravalis (Marusthali) and Kachchh. NCERT names Jaisalmer and Barmer, which receive less than 90 mm of average annual rainfall.
• Severe: eastern Rajasthan, most of MP, eastern Maharashtra, interior AP and the Karnataka plateau, northern interior Tamil Nadu, southern Jharkhand and interior Odisha.
• Moderate: northern Rajasthan, Haryana, southern UP districts, the rest of Gujarat, Maharashtra except Konkan, Jharkhand, the Coimbatore plateau and interior Karnataka.

Consequences. NCERT uses four terms: akal (scarcity of food grains), trinkal (scarcity of fodder), jalkal (shortage of water) and trikal (shortage of all three, the most devastating). Other effects are death of cattle, migration of people and livestock, and waterborne disease from contaminated water.

Measures (NCERT).

• Immediate: safe drinking water, medicines, fodder and water for cattle, and moving people and livestock to safety.
• Long term: identifying aquifers, transferring water from surplus to deficit basins, interlinking rivers, building reservoirs, using remote sensing to plan these, promoting drought-resistant crops, and rainwater harvesting.

Policy instruments (beyond NCERT). NDMA issued National Guidelines on drought management in September 2010; Mains question gs3-pyq-2014-94 asks about these "September 2010 guidelines". The Ministry of Agriculture's Manual for Drought Management dates from 2016. GIDM's drought note lists MGNREGS, PMKSY, crop insurance and watershed works as mitigation measures.

Landslides

NCERT describes a landslide as "the rapid sliding of large mass of bedrocks". Landslides are less dramatic than earthquakes or cyclones, but they block roads, railways and rivers, and a river blocked by a landslide can later flood. Unlike most hazards they are controlled by highly localised factors (geology, slope, land use, vegetation, human activity), which makes monitoring them difficult and costly. NCERT's zones are in Table 6.

Mitigation (NCERT). Restrict roads, dams and other construction in high-vulnerability zones. Limit farming to valleys and moderate slopes. Control large settlements. Promote large-scale afforestation and build bunds to reduce water flow. Encourage terrace farming in the north-eastern hill states where jhumming (shifting cultivation) is still practised. NCERT's exercises and project list also refer to the Malpa landslide in Uttarakhand.

Hazard cascades. On 7 February 2021 in Chamoli, Uttarakhand, about 27 million m³ of rock and glacier ice fell from the north face of Ronti Peak. It became a large debris flow down the Ronti Gad, Rishiganga and Dhauliganga valleys, badly damaged two hydropower projects, and left more than 200 people killed or missing (Shugar et al., Science, 2021, via USGS). It was a rock and ice avalanche, not a glacial lake outburst flood. Several Mains questions use the Himalaya-versus-Western-Ghats contrast: gs1-pyq-2013-22a, gs1-pyq-2016-14, gs1-pyq-2021-06 and gs3-pyq-2021-19.

Disaster management: NCERT's three stages

1. Pre-disaster: data and information on disasters, vulnerability zoning maps, public awareness, planning, preparedness and prevention.
2. During a disaster: rescue and relief, including evacuation, shelters and relief camps, and supply of water, food, clothing and medical aid.
3. Post-disaster: rehabilitation and recovery of victims, and building capacity for future disasters.

NCERT quotes the Disaster Management Bill, 2005 definition of disaster: "a catastrophe, mishap, calamity or grave occurrence affecting any area, arising from natural or man-made causes, or by accident or negligence which results in substantial loss of life or human suffering or damage to, and destruction of, environment, and is of such nature or magnitude as to be beyond the coping capacity of the community of the affected area." It cites the Bill and the establishment of the National Institute of Disaster Management as positive steps. The Bill became the Disaster Management Act, 2005.

The global frame: Yokohama to Sendai

• Yokohama Strategy (May 1994). NCERT's text box covers it in detail. It recognised the sovereign responsibility of each country to protect its citizens, gave priority to developing, least developed, land-locked and small-island states, called for national capacity and legislation, and called for regional and international cooperation on capacity, technology sharing and resources.

• Hyogo Framework for Action, 2005. It is named in Mains question gs3-pyq-2018-18, which asks how Sendai differs from it.

• Sendai Framework for Disaster Risk Reduction 2015-2030. It was adopted at the Third UN World Conference on Disaster Risk Reduction in Sendai, Japan (14-18 March 2015), and endorsed by UN General Assembly resolution A/RES/69/283 on 3 June 2015. It is a voluntary, non-binding framework, adopted rather than signed. It has four priorities:

  1. Understanding disaster risk.
  2. Strengthening disaster risk governance.
  3. Investing in disaster risk reduction for resilience.
  4. Enhancing preparedness for effective response and "Build Back Better" in recovery.

  Its seven global targets are in PART 3.

• Coalition for Disaster Resilient Infrastructure (CDRI). The Prime Minister announced it at the UN Climate Action Summit, New York, on 23 September 2019. It is a partnership of countries, UN agencies, multilateral development banks, the private sector and academia that promotes disaster-resilient infrastructure. Current membership is not stated here because no dated primary count was checked.

PART 3 — UPSC Integration

Sendai Framework: the seven global targets (2015-2030)

Source: UN General Assembly resolution A/RES/69/283 (3 June 2015), Annex II. Mains question gs3-pyq-2024-17 asks for these targets directly.

How the Mains bank uses this chapter

PYQ note: No Prelims question on this chapter is in the bank file that this site resolves (prelims/2026/gs1.json), so prelims_pyq_ids is empty.

Exam Strategy

Prelims fact-traps from this chapter:

• Seismic zones in force: BIS IS 1893 (Part 1):2016 has four zones (II-V). Zone I was merged into Zone II in 2002. The 2025 code with Zone VI was withdrawn on 3 March 2026. A statement that "India currently has six seismic zones" is false as of October 2026.
• NCERT's five zones are damage-risk zones (very high to very low). Do not confuse them with BIS zones II-V.
• NDMA is chaired by the Prime Minister. NCMC is chaired by the Cabinet Secretary, and has had statutory status since the 2025 amendment. UDMA is chaired by the Municipal Commissioner, with the District Collector as vice-chair.
• Drought types (NCERT): meteorological, agricultural, hydrological, ecological. IMD meteorological drought means rainfall below 75% of the long-period average.
• Cyclone latitudes (NCERT): no formation between 0° and 5°. Bay of Bengal October-November cyclones form at 16°-21°N, west of 92°E.
• Flood-prone area: 40 million ha (Rashtriya Barh Ayog). Winter floods: Tamil Nadu (retreating monsoon). Majuli: Brahmaputra.
• Chamoli 2021 was a rock and ice avalanche that became a debris flow. It was not a GLOF.
• Sendai was adopted (18 Mar 2015) and endorsed by the UNGA (3 Jun 2015). It has no "signatories".
• Yokohama: May 1994. IDNDR: 1990-2000.

Mains pattern: Questions either ask for a causal comparison (Himalaya vs Western Ghats landslides, why cyclones concentrate in certain seas) or ask about institutions and approach (reactive vs proactive, Sendai, vulnerability). For the first type, use NCERT's controlling factors. For the second, use the three stages of disaster management, the 2025 amendment's planning and database provisions, and the Sendai targets.

Practice Questions

1. UPSC Mains GS3 2020 (bank ID gs3-pyq-2020-18, 15 marks): "Discuss the recent measures initiated in disaster management by the Government of India departing from the earlier reactive approach."
2. UPSC Mains GS3 2021 (bank ID gs3-pyq-2021-10, 10 marks): "Discuss about the vulnerability of India to earthquake related hazards. Give examples including the salient features of major disasters caused by earthquakes in different parts of India during the last three decades."
3. UPSC Mains GS1 2021 (bank ID gs1-pyq-2021-06, 10 marks): "Differentiate the causes of landslides in the Himalayan region and Western Ghats."
4. Practice (UPSC-pattern, not a past paper): With reference to the Disaster Management (Amendment) Act, 2025, consider the following statements: (1) The National Crisis Management Committee, chaired by the Cabinet Secretary, has been given statutory status. (2) Urban Disaster Management Authorities are to be chaired by the District Collector. (3) The NDMA and SDMAs will themselves prepare the national and state disaster management plans. Which of the statements given above are correct? (1 and 3 only. The UDMA chair is the Municipal Commissioner, and the Collector is vice-chair.)
5. Practice (UPSC-pattern, not a past paper): Which one of the following is the seismic zoning standard in force in India as of October 2026? (a) IS 1893 (Part 1):2002 with five zones (b) IS 1893 (Part 1):2016 with four zones (c) IS 1893 (Part 1):2025 with six zones (d) the NCERT five damage-risk zones (b)

📦 Revision Capsule

Sources

Sources

• NCERT, India: Physical Environment (Class 11), Chapter 6 "Natural Hazards and Disasters", Reprint 2026-27 (rationalised; kegy106.pdf), pp. 53-69. NCERT PDF
• PRS Legislative Research, "The Disaster Management (Amendment) Bill, 2024", bill track and summary (accessed 1 Oct 2026). PRS
• India Environment Portal, "The Disaster Management (Amendment) Act, 2025". IEP
• Bureau of Indian Standards, "Know your standards" record for IS 1893 (Part 1):2025, listing the standard as Withdrawn (accessed 1 Oct 2026). BIS
• C. P. Rajendran, "A Bold Policy Reversed: The Withdrawal Of India's 2025 Seismic Code", ETV Bharat, 11 Mar 2026. ETV Bharat
• National Policy on Disaster Management, 2009 (NDMA), PreventionWeb record. PreventionWeb
• IMD RSMC New Delhi, "Extremely Severe Cyclonic Storm 'FANI' … (26 April-04 May, 2019): Summary". IMD PDF
• Shugar, D. H. et al., "A massive rock and ice avalanche caused the 2021 disaster at Chamoli, Indian Himalaya", Science 373 (2021), DOI 10.1126/science.abh4455. USGS record
• PIB (MoES), "Indian Tsunami Early Warning Centre is providing Tsunami Services to 25 Indian Ocean Countries", 21 Sep 2020. PIB
• US Geological Survey, "Today in Earthquake History: December 26", entry for the M9.1 Sumatra earthquake of 2004 (accessed 2 Oct 2026). USGS
• Human Rights Watch, After the Deluge: India's Reconstruction Following the 2004 Tsunami (May 2005), Ch. II, citing the Home Minister's statement in Parliament of 10 Mar 2005. HRW
• Gujarat Institute of Disaster Management, "Drought: basic concept, types, history" (IMD definition). GIDM PDF
• Business Standard, "India's monsoon rainfall deficit at 14%: When does it become a drought?", 10 Jul 2026 (IMD moderate and severe thresholds). Business Standard
• United Nations General Assembly, resolution A/RES/69/283, "Sendai Framework for Disaster Risk Reduction 2015-2030", 3 June 2015 (UN Digital Library record 795443).
• NICEE, IIT Kanpur, "NICEE Remembers the 1993 Latur Earthquake" (Zone I to Zone III; fatalities). nicee.org/Latur_EQ. The site blocks automated access, and the content was read through search records.