The Indian military evacuated more than 2,000 residents stranded in the southern state of Tamil Nadu on Thursday as the death toll from flooding rose to 269 after the heaviest cloudburst in over a century.
Forecasts of more rain over the next 48 hours forced the army to work on a war footing to rescue survivors trapped in inundated parts of Chennai.
India's fourth most populous city saw only slight rains on Thursday, but water levels had not receded since a day earlier, when a massive release of water from a brimming reservoir swamped low-lying areas of the city.
Prime Minister Narendra Modi, who has blamed climate change for the deluge, traveled to Chennai to get a first-hand view of a rescue effort that has so far been halting.
"The government will stand by the people of Tamil Nadu in their hour of need," Modi told reporters, promising $150 million for rehabilitation and reconstruction.
Even as the weather cleared, waters rose in many residential areas, fed by spills from 35 lakes that have risen to dangerous levels.
After auto manufacturers and IT outsourcing firms suspended operations on Wednesday, state-run Chennai Petroleum shut down its 210,000-barrels-per-day oil refinery due to heavy flooding. The cloudburst earlier this week dumped as much as 345 mm (14 inches) of rain over 24 hours.
"We live in a city expecting that we will have access to basic facilities. But today, we have no drinking water, no fresh food and no control over our lives," said Sudha Raman Murthy, a mother of two teenage daughters.
RESURRECTING A CITY
Soldiers set up 25 temporary shelters and community kitchens and installed portable toilets. "We will have to resurrect an entire city," said Abhijit Shaw, an army officer who was setting up a makeshift maternity ward in a government building.
Floods cut off more than three million people from basic services and hampered rescue efforts by the army, which has so far evacuated 18,000 people from rooftops and outlying villages.
City authorities were deploying bulldozers and bags of concrete to repair collapsed roads and bridges.
Train services and flights to Chennai, capital of Tamil Nadu, were washed out and the navy has pressed fishing boats into service to evacuate people from the worst-hit suburbs to temples, schools and wedding halls.
A senior federal official said more than 1,000 people had been critically injured and were rushed to government hospitals by paramilitary forces.
Additional rainfall of 100 mm to 200 mm (4 inches to 8 inches) was predicted from Thursday through Sunday, keeping the situation critical for several more days.
The federal government also pledged an additional $141 million in immediate relief and began to assess losses to life and property. Assocham, an industry lobby, estimated that financial losses from the floods could exceed $2.25 billion.
Experts said haphazard construction, faulty drainage and a build-up of garbage had contributed to the disaster.
"Chennai is stinking and it is shocking to see how it has collapsed in the last 48 hours," said Anant Raghav, 56, a professor at the University of Madras.
More than 5,000 houses were under water with many people still trapped on rooftops, while others crowded in relief camps.
About 30 families have been sleeping rough under a flyover in central Chennai for the last week, after their huts and small concrete houses were washed away.
Seema Agarwal, from the central district of Alwarpet, said she had seen many angry people queuing at bus stops to leave town.
"There are people who haven't eaten for days," she said. "They have seen their possessions float away from the house. Food, clothes - all gone."