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.
It asks 3 things — 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 rain on paved, encroached cities overwhelms drains within hours; after Mumbai 2005, NDMA was the first to treat urban flooding as a separate disaster.
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, drains that fail for poor maintenance, unplanned growth on floodplains (NDMA).
- Mumbai (26 July 2005): 944 mm in 24 hours at Santa Cruz, choked Mithi river and drains, over 60% of the city inundated.
- Chennai (December 2015): record north-east monsoon rain, encroachments, and release from Chembarambakkam tank without inflow forecasting; 289 lives, 23.25 lakh houses (CAG).
- Frameworks: NDMA Guidelines on Management of Urban Flooding (2010); flood plans under the DM Act 2005.
- Programmes: 15th FC's ₹2,500 crore NDMF for seven cities, AMRUT storm-water drains, Smart Cities, IFLOWS-Mumbai, Model Building Bye-laws 2016, lake restoration.
Close with · Cities must plan with water, not against it: restore wetlands, enforce floodplain zoning and design drains for tomorrow's rainfall, in the spirit of Sendai's Priority 4 to Build Back Better.
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)”
- CAG: the December 2015 Chennai floods claimed 289 lives and inundated 23.25 lakh houses.CAG — Report No. 4 of 2017, Performance Audit of Flood Management and Response in Chennai (executive summary) ↗“The December 2015 floods in the city and its suburban areas claimed 289 lives, inundated 23.25 lakh houses, disrupted power and telecommunication services, halted air, rail and road transport”
- CAG: Chembarambakkam tank had no scientific inflow forecast system or real-time flood forecast mechanism.CAG — Report No. 4 of 2017, Performance Audit of Flood Management and Response in Chennai (executive summary) ↗“Chembarambakkam Tank, despite being a major tank, did not have any scientific inflow forecast system and lacked a mechanism for real time flood forecast”
- CAG: unrestrained encroachments blocked flood flow and inundated parts of Chennai.CAG — Report No. 4 of 2017, Performance Audit of Flood Management and Response in Chennai (executive summary) ↗“Unrestrained encroachments blocked free flow of flood water and had inundated several parts of the city.”
- NDMA: drainage systems fail for poor maintenance, and encroachments are a major problem in many cities.NDMA — Guidelines on Management of Urban Flooding (2010) ↗“Further, the systems very often do not work to the designed capacities because of very poor maintenance. Encroachments are also a major problem in many cities and towns.”
- The Centre approved a ₹561.29 crore integrated urban flood management project for the Chennai basin (central share ₹500 crore).PIB — Urban flood management, 15th Finance Commission recommendations (2024) ↗“Central Government, has approved the project of the Integrated Urban Flood Management activities for Chennai basin of Rs. 561.29 crore, with central allocation of Rs 500 crore.”
Question: UPSC's CS (Main) 2024, GS Paper III — paper ↗. Approach: Minimalist IAS, checked 3 Oct 2026 (how we verify) — UPSC publishes no model answers. ·
Model answer· 368words · Minimalist IAS
Urban floods differ from riverine floods: intense rain on paved, encroached cities overwhelms drains within hours. Hyderabad (2000), Mumbai (2005), Surat (2006) and Kolkata (2007) flooded within one decade, and after Mumbai the NDMA, for the first time, treated urban flooding as a separate disaster.
Causes of this climate-induced disaster
- Climate-induced: more frequent extreme rainfall and cyclonic rain; sea-level rise and tidal backflow that block drainage in coastal cities.
- Encroachment: lakes, wetlands and natural drains built over; NDMA calls encroachments 'a major problem in many cities and towns'.
- Run-off and drains: impervious surfaces raise run-off while drains designed for old rainfall norms fail further for poor maintenance and solid waste choking outfalls.
- Governance: fragmented agencies, weak zoning enforcement and poor real-time rainfall data.
Features of two major floods
| Feature | Mumbai, 26 July 2005 | Chennai, December 2015 |
|---|---|---|
| Trigger | 944 mm in 24 hours at Santa Cruz; high tide | Record north-east monsoon rain; release from Chembarambakkam tank |
| Aggravator | Encroached Mithi river, choked drains | Encroachments blocking flood flow; no inflow forecast at the tank |
| Toll | Over 60% of the city inundated, days of paralysis | 289 lives; 23.25 lakh houses inundated; air, rail and road halted |
- Mumbai's lesson: the 2010 NDMA guidelines urged dense rain-gauge networks, Doppler radar and drainage-network data for early warning.
- Chennai's lesson: the CAG (Report 4 of 2017) found Chembarambakkam had no scientific inflow forecast and that unrestrained encroachments inundated several parts of the city.
Policies and frameworks that aim to tackle such floods
- NDMA Guidelines on Management of Urban Flooding (2010): city drainage plans, dense automatic rain-gauge networks and early warning.
- Disaster Management Act 2005: State and district authorities and plans that now carry urban flood protocols.
- Funding: the 15th Finance Commission's ₹2,500 crore under the National Disaster Mitigation Fund for seven cities; the Centre has approved a ₹561.29 crore integrated urban flood management project for the Chennai basin.
- Programmes: AMRUT storm-water drains, Smart Cities projects, IFLOWS-Mumbai, 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. Sendai's Priority 4, to 'Build Back Better' in reconstruction, is the standard every flooded city should meet.
Prepared by Minimalist IAS to the answer standard of Shivam Singh (mentor, 7 years) · facts checked against official sources (how we verify) · updated 3 Oct 2026. UPSC publishes no model answers: compare your structure and coverage with this, then write your own.
