Floodwaters have started receding from parts of the southern Indian city of Chennai (Madras), hours after it experienced a respite from rain.
More than 7,000 people have been rescued so far, but many are still stranded, reports say.
PM Narendra Modi, who travelled to Chennai, has promised $150m (£99m) to the flood-hit Tamil Nadu state.
More than 260 people have died in the floods in the state after the heaviest rainfall in a century.
A depression in the Bay of Bengal has triggered rains in coastal areas.
Last month, non-stop rain for nearly a week brought the city to a standstill.
Three days of fresh rains have again led to massive flooding, inundating homes, hospitals, roads, railway tracks and the city's airport. Forecasts of more showers remain in place.
Schools, colleges and factories are shut, exams postponed and power supply suspended in most parts of the city. An oil refinery has stopped operations.
Reports say there has been no rain in Chennai on Friday morning and water levels are receding in some parts of the city.
A naval air base at Arakkonam, 70km (43 miles) from the Tamil Nadu state capital, is now being used as a makeshift airport with seven commercial flights expected to operate on Friday and Saturday.
Train services will remain suspended until Saturday, officials say.
At the scene - Sanjoy Majumder, BBC News, Chennai
It hasn't rained in Chennai for 24 hours and with the sun out, the water levels have begun dipping in many parts of the city.
Some areas are still badly affected and remain cut off. Rescue teams are now focussing on these neighbourhoods while trying to get food and medicines to thousands of people who have been affected.
Shops and markets have opened as well and people are queuing up to buy food and fuel, although there are shortages of essentials supplies such as milk.
But the airport and the main railway station are still closed - a naval air base outside the city has been cleared for a limited number of civilian flights.
Although the rain is part of the normal monsoon, Chennai received as much rain in two days as it does in a couple of months.
A massive rescue operation is continuing to reach stranded people. Some 5,000 houses are still under water with many people trapped inside them, reports say.
Troops have set up 25 shelters and community kitchens for the flood victims.
Officials said they were investigating the deaths of 14 patients on life support after a power failure at a private hospital in the city.
"The hospital was flooded and it was adjacent to the river. The patients have died over a period of three days. 57 other patients who were also on ventilator support have been shifted to other hospitals in the city,'' Tamil Nadu health official J Radhakrishnan told the BBC Hindi.
"The deaths have definitely not occurred due to power cuts. They were all critical patients. This will in any case be a matter of investigation," he said.
Seema Agarwal, a resident, said she had seen many people queuing at bus stops to leave the city.
"There are people who haven't eaten for days. They have seen their possessions float away from the house. Food, clothes - all gone," she told the Reuters news agency.
The federal weather office has predicted two more days of torrential rain in the southern state, where nearly 70 million people live.
A total of 269 people are now known to have died in floods in Tamil Nadu state since last month.