MUMBAI - Torrential rain lashed India's financial capital Mumbai, triggering floods and killing at least four people as well as paralyzing the city and forcing schools to close on Thursday before easing slightly in the afternoon.

Some parts of Mumbai recorded around 275 mm of rain on Wednesday evening, which crippled road traffic and delayed the trains millions of city residents use every day.

Four people died from rain-related incidents, officials said.

Prime Minister Narendra Modi cancelled a trip to the city of Pune, nearly 200 km from Mumbai, after authorities declared a red alert due to the rain.

With more rain expected in Mumbai as well, authorities also issued a citywide red alert and urged residents to stay home. Schools and colleges were shut and fishermen were asked to stay away onshore until Friday.

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Drone footage posted on social media showed snarled highways clogged with cars - some with their drivers still inside, others abandoned by frustrated drivers. Hundreds of thousands of commuters spent hours on the road.

India's monsoon rains started retreating from the northwest of the country earlier this week, nearly a week later than normal, the state-run India Meteorological Department (IMD) said in a statement.

The monsoon generally begins in June and starts to retreat by Sept 17 but the rains continued this year, which has helped to replenish reservoirs but damaged the crop harvest in some states.

Heavy rain was also forecast for some parts of the southern state of Telengana on Thursday, the weather office said.

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In neighboring Bangladesh, rain brought relief after a week of intense heat, but it also flooded streets, worsening the already bad traffic in the capital Dhaka and other parts of the country.