Torrential downpours have been lashing Mumbai since Saturday morning, but inflicted a heavy toll on the city's beleaguered population and transport infrastructure Tuesday, when the city endured its heaviest rains since 2005.
More heavy rains had been forecast for Wednesday, forcing the government to order schools and colleges shut, but in many areas the downpours were lighter.
The India Meteorological Department has predicted that Mumbai may receive very heavy rainfall in the next 48 hours.
Residents of Dharavi, one of Asia's biggest slums and home to more than a million people, said much of the low-lying area was under water.
Mumbaikars were brought to their knees on Tuesday, as torrential rain pounded the metropolis, inundating almost the entire island and its suburbs, crippling normal life and bringing back unpleasant memories of the July 26, 2005 deluge.
The Mumbai police have asked people who have got stranded due to heavy rainfall to dial police emergency no 100 or send message on their twitter handle to seek any kind of assistance.
Lakhs of commuters including students were stranded in trains, railway stations or at bus stops.
Although Mumbai is trying to build itself into a global financial centre, parts of the city struggle to cope during annual monsoon rains. Heavy downpour and strong winds left airport in the financial capital nearly crippled with long delays, forcing airlines to divert many flights to other cities or making aircraft to do go-arounds through the day today.
Since Tuesday morning, many parts of Mumbai and suburbs were inundated with up to three to four feet of water on the highways, main and arterial roads, bylanes, housing complexes, railway stations and even the Mumbai Airport.
The hardest-hit areas reported as much as 150 mm (6 inches) within an hour on Tuesday. The train commuters had harrowing experiences in CR, WR and Harbor Line because they were running late due to flooded tracks.
But Mumbai already has had about 2,000 mm of rainfall this monsoon season (since June) which is more than normal.
Officials are calling on people to stay at home.