Why Indian Cities Flood After Heavy Rain and Overheat in Summer Every Year

Recent extreme heat in Delhi-NCR and heavy rainfall causing urban flooding have highlighted how poor urban planning converts weather hazards into recurring disasters.

When Does a Natural Hazard Become an Urban Disaster?

• A heatwave, cloudburst or cyclone becomes a disaster when it affects highly exposed populations and infrastructure with inadequate capacity to withstand it.
• Heavy rainfall causes severe flooding when drains are narrowed, lakes and floodplains are encroached upon and land is covered with concrete.
• Dense construction, asphalt surfaces, poor ventilation and loss of trees create urban heat islands that retain heat even after sunset.

Why Are Indian Cities Becoming More Vulnerable?

• Climate change is intensifying heatwaves and extreme rainfall, while rapid urbanisation is replacing soil, vegetation and water bodies with hard surfaces.
• Indian city centres can be around 3–4°C hotter than surrounding areas, according to World Bank estimates.
• India’s urban population is projected to reach around 951 million by 2050, significantly increasing exposure to climate hazards.
• More than half of the urban infrastructure India will need by 2050 is yet to be built, making future planning decisions crucial for resilience.

What Do These Disasters Cost?

• Timely adaptation could prevent annual urban flood losses of around $5 billion by 2030 and $30 billion by 2070, according to the World Bank.
• Measures addressing extreme heat could potentially save more than 130,000 lives by 2050.

What Has Changed in the Law?

• The 2025 amendment to the Disaster Management Act, 2005 enables States to establish Urban Disaster Management Authorities in State capitals and municipal-corporation cities, except Delhi and Chandigarh.
• Urban Disaster Management Authorities are responsible for preparing and implementing city-specific disaster management plans.
• In August 2026, heatwaves and lightning were included among notified natural calamities, enabling eligible relief expenditure from disaster-response funds.
• Heatwave mitigation projects can also receive financial support through disaster mitigation funds.

Where Does the System Fall Short?

• States have discretion over establishing Urban Disaster Management Authorities and the law specifies no mandatory deadline for their creation.
• Urban disaster management remains fragmented among municipal corporations, district administrations and State departments in most cities.
• A 2021 NITI Aayog report found that 65% of India’s 7,933 urban settlements lacked a master plan.
• Shortages of qualified planners and understaffed planning departments weaken the ability of cities to prepare for climate-related disasters.

What Would Reduce the Risk?

• Flood-risk maps should guide construction restrictions, drainage capacity and minimum building-plinth requirements.
• Heat-risk maps should guide requirements for shade, ventilation, tree cover and climate-appropriate building materials.
• Urban local bodies need more qualified planners and technical experts to integrate disaster resilience into development decisions.
• Infrastructure approvals should clearly assign responsibility, implementation timelines and accountability for resilience measures.
• Disaster financing should move beyond post-disaster relief towards prevention, adaptation and mitigation investments.
• Early-warning systems should trigger measures such as changes in outdoor working hours, hospital preparedness, school closures and traffic diversions.
• Repeated flooding and overheating in the same locations indicate failures of urban planning and governance rather than weather alone.