Chennai floods: Why are deadly monsoons hitting the city so hard?

At least 188 people are dead after the heaviest rainfall in a century hits the Indian city of Chennai

An Indian family wade through the flood waters in Chennai (Getty Images)

At least 188 people have been killed after torrential downpours caused major flooding in the Indian state of Tamil Nadu.

The state capital, Chennai, experienced its heaviest rainfall in more than a century on Wednesday, with more rain expected.

Schools, factories and roads have been forced to close with thousands believed to have been forced from their homes.

Why is the Monsoon hitting Chennai so hard?

Monsoon rains are a typical feature of the climate in this region but the city is particularly badly hit because its coastline faces the Bay of Bengal.

Low pressure in the atmosphere around the bay is believed to have caused the extra, heavier rains.

Has it been caused by climate change?

It is unclear. Studies have looked at the changing patterns in the monsoon season across the region over the past 50 years.

Scientists are unsure about whether the change is manmade but late monsoons increase the likelihood of both droughts and floods.

They say this year’s monsoons are likely to have been affected by the El Nino phenomenon - which increases instances of extreme weather around the world and occurs roughly every seven to 10 years.

What about development?

According to research by the World Bank, Chennai - along with Mumbai and Kolkata - is one of the most vulnerable coastal cities in the world.

India Today reports the massive development of the city over the past 15 years is partly to blame for the flooding.

It said the decision to use up marshland for housing without planning permission has meant the land is no longer as absorbent and there is nowhere for storm water to drain.

Building work has also encroached onto river banks - making them more vulnerable when the rivers burst their banks.

An editorial in The Hindu called on city planners to do more, saying the floods “highlighted the inadequate level of preparedness”.