Heavy monsoon rains have brought relief to India's financial and entertainment capital Mumbai, helping to ease a water shortage but causing flooding in many parts of the city and travel chaos.

A lack of consistent rain since the start of the monsoon season in June left levels dangerously low at the lakes that supply the city with 3.3 billion litres (872 billion US gallons) a day and prompted a 30 percent cut in supplies.

But downpours since Monday night have made up for the shortfall in the city of 18 million. Some 82.9 millimetres (3.3 inches) fell in Colaba, south Mumbai, and 274.1 mm in the western Santa Cruz district in the 24 hours to 8:30 am (0300 GMT) Wednesday.

Since June 1, 883 mm of rain has fallen in Colaba -- still down 54.5 mm on average annual levels -- and 1,116 mm in Santa Cruz, 186.5 mm more than usual, the Indian Meteorological Department said on its website.

Water stocks improved dramatically due to the rains, Mumbai's civic authorities said, with the heavy rain giving 10 more days supply.

Last week, officials warned that some suburbs could have just 20 days more water and said they were considering cloud-seeding to make it rain.

"If it continues to rain in this manner steadily, the current water crisis will recede," senior Brihanmumbai Municipal Corporation official Anil Diggikar was quoted as saying by the Times of India newspaper.

"Very heavy rain" -- classified as between 124.5 and 244.4 mm -- is forecast for the next 24 hours, the meteorological department said.

Mumbai lives in fear of a repeat of devastating floods in July 2005 that left nearly 450 people dead and killed close to 1,100 elsewhere in Maharashtra state.

Several lower-lying areas of the island city were flooded, making some roads impassable and forcing pedestrians to wade waist-deep in murky water. Schools and colleges were shut while many office workers chose to stay at home.

Train services on the two main railway lines that serve the city were also affected while flights in and out of Mumbai's international and domestic airports were delayed.

Bollywood megastar Amitabh Bachchan was one of many Mumbaikars affected. He wrote on his blog that his ground floor office was inundated and he was forced to move belongings as waters threatened to encroach into his Juhu home.