The monsoon rains continuing for already three days in the Indian city of Mumbai (Bombay) and the surrounding region of Maharashtra have left for about 430 people dead.
Outside Mumbai, two of the worst-hit areas are Raigad and Ratnagiri districts.
In one village south of Mumbai, work is under way to extract the bodies of some 100 people thought to have been buried by mud, BBC reports.
People killed in the city were crushed by falling walls, trapped in cars or electrocuted.
Aslam Khan witnessed the collapse of a small hill on to the northern suburb of Saki Naka.
"I was scared the hill would fall," he was quoted as saying by BBC. "I kept telling my cousin 'Let's leave' but he wouldn't listen. Now it's too late."
More than 65cm (26 inches) of rain fell in Mumbai on Tuesday. "This is the highest-ever recorded in India's history," Mr Sharma said.
Bodies were piled onto trucks and private cars were flagged down to carry the injured to hospitals.
"People ran as soon as the hill started crumbling. But the old people had no chance," said Shabana Shaikh, who lost her parents in the landslide. She said authorities had asked shanty dwellers each year to vacate their decrepit homes.
Hundreds of Bombay residents began returning to their homes early Thursday in the worst-affected parts of the city's suburbs after spending two nights stranded in offices, buses, cars or trains, AP informs.
The deluge was unprecedented in Bombay, a hectic, cosmopolitan city that is home to India's financial and movie industries, as well as some of its worst poverty.
Every year, Mumbai comes to a halt for a day or two due to heavy monsoon rains, which pound the country between June and September and often leave hundreds dead across India. But this week's downpours left the city paralyzed.
"Most places in India don't receive this kind of rainfall in a year. This is the highest ever recorded in India's history," said R.V. Sharma, director of the meteorological department in Mumbai.
India's previous heaviest rainfall, recorded in the northeastern town of Cherrapunji, was 838 millimetres on July 12, 1910.