Chapter 2 · Topic 2.3 · Prelims + Mains3 of 3
Specific Disasters & Mitigation: Chapter review
Key points
- Drought has three stages (rain, soil, water bodies); India declares it under the Manual for Drought Management (2016, updated 2020).
- IMD heatwave (plains): at least 40°C and 4.5–6.4°C above normal, or 45°C or more; severe: 47°C or more.
- Wet-bulb 35°C is the limit beyond which sweating can't cool the body; Ahmedabad's Heat Action Plan (2013) was South Asia's first.
- Bhopal (1984) is the worst industrial disaster; key rules are MSIHC 1989, PLI Act 1991, EPPR 1996.
Prelims box: facts and traps
| Category | IMD rule (plains) |
|---|---|
| Heatwave | Max at least 40°C and 4.5–6.4°C above normal, or actual 45°C or more |
| Severe heatwave | More than 6.4°C above normal, or actual 47°C or more |
| Coastal stations | Max at least 37°C |
| Hill stations | Max at least 30°C |
- Ahmedabad’s Heat Action Plan (2013) was the first in South Asia; NDMA's national heatwave guidelines came in 2016.
- The Bhopal gas tragedy (2–3 December 1984) was a methyl isocyanate leak from the Union Carbide plant.
- Trap: the Public Liability Insurance Act, 1991 pays relief regardless of fault (no-fault liability).
Droughts and heatwaves
Drought comes in three stages: too little rain (meteorological), dry soil hurting crops (agricultural), and empty rivers, tanks and wells (hydrological).
Mains 2014 noted: Drought has been recognized as a disaster in view of its spatial expanse, temporal duration, slow onset, and lasting effects on vulnerable sections. Simply: big area, long, slow, hurts the poor. It asked about preparedness for El Niño (usually a weaker monsoon) and La Niña (usually heavier rain) under the September 2010 NDMA guidelines:
- drought monitoring cells, contingency crop plans (backup crops if rain fails), water budgeting, fodder banks, MGNREGA works and crop insurance.
The Manual for Drought Management (2016, updated 2020) declares drought using rainfall, vegetation, soil moisture and water indices.
Drought has been recognized as a disaster in view of its spatial expanse, temporal duration, slow onset and lasting effects on vulnerable sections. With a focus on the September 2010 guidelines from the National Disaster Management Authority (NDMA), discuss the mechanisms for preparedness to deal with likely El Nino and La Nina fallouts in India.
| IMD heatwave rule (plains) | Value |
|---|---|
| Heatwave | Max at least 40°C and 4.5–6.4°C above normal, or actual 45°C or more |
| Severe heatwave | More than 6.4°C above normal, or actual 47°C or more |
| Coastal stations | Max at least 37°C with the same departures |
| Hill stations | Max at least 30°C with the same departures |
Source: IMD criteria.
UPSC Prelims 2025 noted: The World Bank warned that India could become one of the first places where wet-bulb temperatures routinely exceed 35°C. Wet-bulb temperature mixes heat and humidity. At 35°C, sweat stops drying, so the body can’t cool itself. Both statements were correct: peninsular India faces floods, cyclones and droughts, and at such levels bodies cannot shed heat. Answer: both I and II (c). Ahmedabad’s Heat Action Plan (2013) was the first in South Asia. NDMA issued national heatwave guidelines in 2016.
The World Bank warned that India could become one of the first places where wet-bulb temperatures routinely exceed 35°C. Which of the following statements best reflect(s) the implication of the above-said report? I. Peninsular India will most likely suffer from flooding, tropical cyclones and droughts. II. The survival of animals including humans will be affected as shedding of their body heat through perspiration becomes difficult. Select the correct answer using the code given below.
- I only
- II only
- Both I and II
- Neither I nor II
Show answer
Answer: (c) · UPSC official key
What UPSC asks: Drought Manual 2016, wet-bulb 35°C.
Industrial, chemical and CBRN disasters
The Bhopal gas tragedy (2–3 December 1984), when methyl isocyanate leaked from the Union Carbide plant, is the world’s worst industrial disaster. The styrene leak at LG Polymers, Visakhapatnam (May 2020) showed that the risk remains.
| Law or guideline | What it does |
|---|---|
| Environment (Protection) Act, 1986 | Umbrella law for hazardous substances |
| Hazardous Chemicals (MSIHC) Rules, 1989 | Site safety reports and on-site emergency plans |
| Chemical Accidents (EPPR) Rules, 1996 | Crisis groups at Centre, State, district and local level |
| Public Liability Insurance Act, 1991 | Immediate relief to victims regardless of fault |
| NDMA guidelines | Chemical (2007), biological (2008), nuclear and radiological (2009) disasters |
CBRN stands for chemical, biological, radiological and nuclear emergencies. NDRF battalions are trained and equipped for CBRN response, and hospitals need decontamination (cleaning poison off people) and isolation plans. Mains tip: dangerous plants should not sit inside crowded towns.
What UPSC asks: Bhopal 1984, EPPR Rules 1996.
Mains box: analysis and answer points
- Drought preparedness (Mains 2014, 12.5 marks): El Niño and La Niña effects, then the 2010 NDMA tools: monitoring cells, contingency crop plans, water budgeting, fodder banks, MGNREGA, crop insurance.
- Heat: IMD thresholds, wet-bulb 35°C, Heat Action Plans.
- Next likely angle: heat as a disaster and CBRN preparedness.
Practice
Write an answer
In 150 words, explain the significance of Specific Disasters & Mitigation with one recent example.
Flashcards (5)
Drought Manual?
2016, updated 2020.
Heatwave in plains?
At least 40°C and 4.5°C above normal.
First South Asian Heat Action Plan?
Ahmedabad, 2013.
Bhopal gas?
Methyl isocyanate, December 1984.
EPPR Rules?
1996, chemical accident crisis groups.
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Next chapter · 3. Community & Technology in DM →Community & Technology in DM: Community-based disaster management