Five children were among six killed when a building collapsed in Mumbai, officials said on Monday, as monsoon rains pounded India’s financial capital, flooding roads and leading to school closures.

A dilapidated residential building collapsed on Sunday in the megacity’s east, trapping residents under the debris, Mumbai Mayor Ritu Tawde said in a statement.

The deaths came as heavy rainfall paralysed parts of the city, with the India Meteorological Department recording more than 200 millimetres of rain within 24 hours.

Hundreds of millions of people in India rely on the annual monsoon winds to bring vital rains that sustain agriculture and industry.

However, climate change is shifting weather patterns and making the world’s most populous country hotter. This year’s El Niño weather phenomenon has prompted warnings of lower rainfall.

The weather office has issued a red alert warning for Mumbai on Monday, forecasting continued heavy rain and gusty winds.

With roads inundated, Mumbai authorities declared Monday a holiday for all schools and colleges.

Mayor Tawde called on people to stay indoors if possible, warning of falling trees and branches due to strong winds.

The downpours in Mumbai follow weeks of sweltering heat, with authorities imposing restrictions on water use last month and cutting supplies to swimming pools and construction sites.

The city of over 20 million people is grappling with concerns over pressure on water resources from expanding data-centre infrastructure, whose large cooling requirements could exacerbate supply strains.