Flooding in urban areas is an emerging climate-induced disaster. Discuss the causes of this disaster. Mention the features of two such major floods in the last two decades in India. Describe the policies and frameworks in India that aim at tackling such floods.
Approach · directive: “discuss / mention / describe”
What it asks · Explain why Indian cities flood, describe two major urban floods, and outline the policy frameworks against them.
The question has 3 parts — answer each
- Discuss the causes of urban flooding: climate-induced and urban
- Mention the features of two major urban floods of the last two decades in India
- Describe the policies and frameworks in India that aim to tackle urban floods
Open with · Urban floods differ from riverine floods: intense rainfall on paved, encroached cities overwhelms drains within hours.
Cover
- Climate: more frequent extreme rainfall events and cyclonic rain; sea-level rise and tidal backflow in coastal cities.
- Urban causes: encroached lakes and drains, impervious surfaces, undersized and clogged drains, unplanned growth on floodplains.
- Mumbai (July 2005): extreme rainfall on 26 July, choked Mithi river and drains; heavy loss of life and a city at standstill.
- Chennai (December 2015): very heavy rain, encroached water bodies and a large reservoir release flooded vast areas.
- Frameworks: NDMA Guidelines on Management of Urban Flooding (2010); flood plans under the DM Act 2005.
- Programmes: AMRUT storm-water drains, Smart Cities, flood warning systems such as IFLOWS-Mumbai, and restoration of urban lakes.
- Gaps: weak enforcement of zoning, fragmented agencies, and outdated drainage design standards.
Close with · Cities must plan with water, not against it — restore wetlands, enforce floodplain zoning and design drains for tomorrow's rainfall.
Add value (verified)
- NDMA was the first to treat urban flooding as a separate disaster, after the Mumbai floods of July 2005. NDMA — Guidelines on Management of Urban Flooding (2010) ↗“NDMA has for the first time decided to address urban flooding as a separate disaster, delinking it from floods.”
- Mumbai, 26 July 2005: 944 mm of rain in 24 hours at Santa Cruz; over 60% of the city was inundated (NDMA guidelines). NDMA — Guidelines on Management of Urban Flooding (2010) ↗“On 26th July 2005, Mumbai suffered severe flooding due to 944 mm rainfall in 24 hours recorded at Santa Cruz observatory at Mumbai airport. According to the Government of Maharashtra, over 60 % of Mumbai city was inundated to various degrees.”
- The 15th Finance Commission recommended ₹2,500 crore under the NDMF for urban flood management in seven cities — ₹500 crore each for Mumbai, Chennai and Kolkata and ₹250 crore each for Bengaluru, Hyderabad, Ahmedabad and Pune. PIB — Threat of Urban Floods (MHA, 6 February 2024) ↗“Fifteenth Finance Commission has recommended an allocation of Rs. 2,500 Crore under National Disaster Mitigation Fund (NDMF) over its award period to prepare integrated solutions for flood management for three metro cities (Mumbai, Chennai and Kolkata)”
Question: UPSC's CS (Main) 2024, GS Paper III — paper ↗. Approach: Minimalist IAS, checked 30 Sept 2026 (how we verify) — UPSC publishes no model answers. ·
Model answer · 294 words (UPSC limit 250) · Minimalist IAS
Urban floods differ from riverine floods: intense rain on paved, encroached cities overwhelms drains within hours, and climate change is making such cloudbursts more frequent.
Causes
- Climate-induced: more frequent extreme rainfall and cyclonic rain; sea-level rise and tidal backflow that block drainage in coastal cities.
- Urban: lakes, wetlands and natural drains encroached; impervious surfaces raise run-off; undersized, clogged drains built for old rainfall norms; growth on floodplains and low-lying land; solid waste choking outfalls.
- Governance: fragmented agencies, weak enforcement of zoning and building rules, and poor real-time rainfall data.
Two major floods
- Mumbai, 26 July 2005: 944 mm of rain in 24 hours at Santa Cruz; the encroached Mithi river and choked drains, with a high tide, inundated over 60% of the city; heavy loss of life and days of paralysis led NDMA to treat urban flooding as a distinct disaster.
- Chennai, December 2015: very heavy north-east monsoon rain, encroached Pallikaranai marsh and the Adyar–Cooum floodplains, and a large release from Chembarambakkam reservoir flooded vast areas and shut the airport for days.
Policies and frameworks
- NDMA Guidelines on Management of Urban Flooding (2010): the first to treat it separately, prescribing city drainage plans, dense rain-gauge networks and early warning.
- Disaster Management Act 2005: State and district authorities and plans that now include urban flood protocols.
- Funding: the 15th Finance Commission's ₹2,500 crore under the National Disaster Mitigation Fund for integrated flood management in Mumbai, Chennai and Kolkata and flood prevention in Bengaluru, Hyderabad, Ahmedabad and Pune.
- Programmes: AMRUT storm-water drains, Smart Cities projects, IFLOWS-Mumbai and similar warning systems, Model Building Bye-laws 2016 mandating rainwater harvesting, and restoration of urban lakes and wetlands.
Cities must plan with water, not against it — restore wetlands, enforce floodplain zoning and design drains for tomorrow's rainfall, not yesterday's.
Written by Minimalist IAS from facts checked at source (how we verify) — a little fuller than exam length, so every part of the question is covered; in the hall, keep the structure and trim the detail. UPSC publishes no model answers: compare your structure and coverage with this, then write your own.