Natural Hazards and Disasters

India is one of the world's most disaster-prone countries — exposed to 85% of natural hazard types. Every year, floods, cyclones, droughts, earthquakes, and landslides collectively affect tens of millions of people and cause economic losses worth billions of dollars. The distinction between a natural hazard (a potential threat) and a disaster (when a hazard causes harm to people and livelihoods) frames the entire field of disaster management — and this distinction is the starting point for UPSC answers on this topic.

This chapter is directly mapped to GS Paper 3 (Disaster Management) and GS Paper 1 (Indian physical geography). The Disaster Management Act 2005, NDMA, Sendai Framework, and IMD's cyclone tracking system are all examined by UPSC.

PART 1 — Quick Reference Tables

Table 1: Hazard vs Disaster — Key Distinctions

Table 2: India's Seismic Zones

Table 3: Cyclones in India — Bay of Bengal vs Arabian Sea

Table 4: Types of Floods in India

Table 5: Droughts in India — Classification

PART 2 — Detailed Notes

Hazard, Vulnerability, and Disaster

The hazard–vulnerability–capacity framework is central to modern disaster management:

• Hazard: A natural event with potential to cause harm (earthquake, cyclone, flood, drought, tsunami)
• Vulnerability: The degree to which people, livelihoods, and assets are susceptible to harm — determined by poverty, building quality, location, access to information, governance
• Capacity: Resources, skills, systems available to resist and recover
• Disaster = Hazard × (Vulnerability / Capacity): The same earthquake destroys a poorly-built city but causes minimal damage in an earthquake-resistant one (Haiti 2010 vs Chile 2010 — similar magnitude, vastly different outcomes)

India's high disaster risk stems not from exceptional hazard levels but from high vulnerability — dense population in hazard-prone zones, poor-quality housing, poverty limiting preparedness, and historical gaps in warning systems.

Earthquakes: India's Seismic Risk

About 59% of India's land area is in seismic zones III, IV, and V — at risk from moderate to very high earthquake intensity.

Causes of India's seismicity:

• The Indo-Australian Plate continues pushing northward into the Eurasian Plate at ~5 cm/year. This compressional force builds stress in the Himalayan mountain belt and causes periodic release as earthquakes.
• The Himalayan region (zones IV–V) is particularly active.
• Intraplate earthquakes also occur within the stable Peninsular Plate, often unpredictably — the Latur/Killari earthquake (1993) in Maharashtra (zone II–III) killed ~9,748 people, demonstrating that even "low seismic" zones can have devastating earthquakes.

Major India earthquakes:

• Shillong (1897): 8.1 Mw
• Kangra, HP (1905): 7.8 Mw
• Bihar-Nepal (1934): 8.2 Mw — 30,000 deaths
• Bhuj, Gujarat (2001): 7.7 Mw — 13,805+ deaths, 340,000+ collapsed structures
• Jammu & Kashmir (2005): 7.6 Mw — 79,000 deaths (mostly Pakistan-side)
• Sikkim (2011): 6.9 Mw

Tsunami: The 2004 Indian Ocean Tsunami (9.1 Mw, offshore Sumatra) killed ~230,000 across 14 countries; ~12,405 in India (Tamil Nadu, Andaman & Nicobar). This event triggered the establishment of the Indian Tsunami Early Warning System (ITEWS) at INCOIS (Hyderabad), which now provides alerts within 5–10 minutes of a seismic event.

💡 Explainer: Cyclone Formation and India's Preparedness

Cyclone formation (over Bay of Bengal typically):

1. Warm sea surface temperature (>26°C) provides energy
2. Low-level convergence and spin (5°–20° latitude for Coriolis effect)
3. Ascending moist air forms massive cumulonimbus clouds
4. Latent heat release drives further convection → self-sustaining vortex
5. Intensification: Cyclone → Deep Depression → Cyclonic Storm → Very Severe → Super Cyclonic Storm

IMD's cyclone track and warning system has dramatically improved — lead time before landfall now 3–5 days for track and 48 hours for intensity. Odisha's cyclone preparedness is a global model:

• After Cyclone Super Cyclone 1999 (Odisha, 10,000+ deaths), massive investment in coastal embankments, cyclone shelters, and warning systems
• Cyclone Fani (2019, 250 km/h) — 1.2 million people evacuated in 48 hours → only 64 deaths (vs similar strength cyclones killing thousands elsewhere)

NDRF (National Disaster Response Force): Established under the Disaster Management Act 2005; 16 battalions; specialised training for various disasters; pre-positioned before cyclone season along vulnerable coasts.

Floods: India's Most Widespread Disaster

India accounts for ~10% of world's flood deaths. Brahmaputra–Ganga–Barak basin (Assam, Bihar, UP, West Bengal) is India's most flood-prone region.

Why Assam floods so severely:

• Brahmaputra carries one of the world's highest sediment loads → raises riverbed → increases overflow
• Narrow, constrained valley → rapid water level rise
• Deforestation upstream → faster runoff
• Annual flooding inundates Kaziranga National Park — rhinos, tigers, elephants displaced onto National Highway 37

Urban flooding has emerged as a major 21st-century risk:

• Mumbai floods (2005): 944 mm rainfall in 24 hours; 1,094 deaths; city paralysed
• Chennai floods (2015): October–December; over 300 deaths; ₹20,000+ crore damage
• Bengaluru floods (2022): Encroachment on wetlands and storm water drains
• Cause: rapid urbanisation without integrated drainage planning; construction on floodplains; inadequate stormwater infrastructure

India's Drought Zones

The drought-prone areas of India include:

• Rajasthan: Annual rainfall <200 mm; frequent meteorological droughts
• Vidarbha (Maharashtra): Semi-arid; cotton-growing; farmer suicides linked to drought-debt cycle
• Marathwada (Maharashtra): Severe water scarcity; Latur tanker water supply
• Bundelkhand (UP–MP border): Dryland agriculture; chronic water shortage
• Saurashtra–Kutch (Gujarat): Coastal arid; improved by Sardar Sarovar canal
• Rayalaseema (AP): Low rainfall; dependent on Krishna–Tungabhadra waters

Drought management in India: PM AASHA scheme (price support for oilseeds/pulses); MGNREGS (employment during drought); Pradhan Mantri Fasal Bima Yojana (crop insurance); National Drought Management Policy 2016.

Landslides: Mountain Hazards

India's landslide-prone zones:

1. Himalayas: Young, unstable rocks; heavy monsoon; road construction; seismic activity. Major events: Kedarnath 2013 (composite: cloud burst + flash flood + landslide; ~5,000 deaths); Chamoli GLOF 2021 (Tapovan dam workers killed); Joshimath (2023, subsidence)
2. Western Ghats: Heavy monsoon rainfall (3,000–4,000 mm/yr); laterite slope failure. Kerala: Munnar, Wayanad (Wayanad landslide, July 2024 — >400 deaths; one of worst in recent history)
3. Northeast India: Heavy rainfall; unstable hill terrain; widespread jhum cultivation destabilises slopes

Triggers: Heavy/prolonged rainfall, earthquakes, slope undercutting by rivers, road construction, deforestation.

🎯 UPSC Connect: Institutional Framework

Disaster Management Act, 2005: The legal backbone of India's DM system.

• NDMA (National Disaster Management Authority): Chaired by PM; sets policies, guidelines; coordinates national response
• SDMA (State DMA): Chaired by CM; state-level planning
• DDMA (District DMA): Chaired by District Collector/Magistrate; front-line response
• NDRF (National Disaster Response Force): 16 battalions (each ~1,149 personnel); specialised response teams

Sendai Framework for Disaster Risk Reduction (2015–2030): India is a signatory. Four priorities:

1. Understanding disaster risk
2. Strengthening disaster risk governance
3. Investing in DRR for resilience
4. Enhancing disaster preparedness for effective response

Coalition for Disaster Resilient Infrastructure (CDRI): Launched by India at UNGA 2019; India's multilateral initiative; >50 countries; focus on making infrastructure (transport, energy, telecom) resilient to natural hazards and climate change.

PART 3 — Frameworks & Analysis

Disaster Types: India's Vulnerability Matrix

Sendai Framework Targets (2015–2030)

Exam Strategy

Prelims Traps:

• Hazard ≠ Disaster — the key distinction is human vulnerability. An earthquake in an uninhabited region is a hazard, not a disaster.
• India has 5 seismic zones (I–V) — but only zones II–V are shown on official BIS maps (Zone I was absorbed into Zone II).
• Zone V is highest risk (not Zone 1). Delhi is in Zone IV (high risk).
• Bay of Bengal produces more cyclones than the Arabian Sea — primarily because it is enclosed, has warmer SST, and river discharge reduces salinity.
• Cyclone Fani (2019) was an extraordinary success story of early warning + mass evacuation — know this example.
• NDMA is chaired by the Prime Minister (not the Home Minister).

Mains Frameworks:

• For any disaster management answer: Hazard × Vulnerability / Capacity → Prevention/Mitigation → Preparedness → Response → Recovery → DM Act 2005 framework.
• Cyclone preparedness: Odisha model (shelters + warning + evacuation) → compare with earlier disasters.
• Climate change + disasters: linking intensifying cyclones, increased flash floods, GLOFs to climate change → CDRI, NAPCC.
• CDRI: India's international initiative → resilient infrastructure → mention as India's global contribution.

Practice Questions

1. UPSC Prelims 2021: Which of the following statements is correct about the National Disaster Management Authority? (Chaired by the Prime Minister; established under DM Act 2005)
2. UPSC Prelims 2019: Which part of India has the highest seismic risk (Zone V)? (Northeast India, Kashmir, Himachal, Uttarakhand, Andaman & Nicobar)
3. UPSC Mains GS3 2020: Explain the factors responsible for the high vulnerability of India to natural disasters. Discuss the institutional framework to manage them.
4. UPSC Mains GS3 2021: "India has made significant progress in disaster preparedness, but the rising intensity of climate-related disasters poses new challenges." Examine.