2 weeks ago

Why Mumbai Streets Flood After Just One Hour of Rain

Imagine the air above a city is like a giant sponge.

When the air gets warmer, the sponge grows bigger and can hold more water.

When this big sponge finally squeezes, it drops a lot of rain all at once.

That is why one hour of rain can feel like a whole season.

But the rain is only half of the story.

Water used to soak into the ground or flow away through rivers and wetlands.

People built roads and buildings on top of those spongy places, so the water has nowhere to go.

It sits on the hard concrete and fills the streets.

A city can fix part of this by collecting rainwater, keeping drains clear, and protecting wetlands and mangroves.

So when you see a flooded street, remember: too much water came down, and there was nowhere for it to go.

Key facts

Benchmark flood event: 944 mm of rain in 24 hours on 26 July 2005 in Mumbai
Wetland loss: Mumbai and Thane lost roughly 40% of their wetlands to construction between the early 1990s and 2005
Mithi River shrinkage: Narrowed by encroachment and building to about half its former size
Extreme rainfall trend: Extreme rainfall events over central India roughly tripled between 1950 and 2015
Atmospheric effect: Air can hold about 7% more water for every 1°C of warming
2025 rainfall record: IMD recorded a sharp rise in extreme-rainfall events; rain-related disasters became India's deadliest climate hazard that year
Drainage limit: Parts of Mumbai would still flood from a 2005-type downpour even with drains upgraded to clear 50 mm per hour
Rainwater harvesting rule: Mandatory in Mumbai for societies over 300 sq m; the BMC offers a property-tax rebate for eco-measures

thebetterindia.com · 2 weeks ago