The "heaviest rains in 70 years" lashed Shanghai Thursday, flooding 3,000 homes and leaving nearly 2,000 travellers stranded at the city's airports, state media reported.

Between 80 to 140 millimetres (three to 5.5 inches) fell in most areas of China's largest city, official news agency Xinhua reported, adding that vehicles had been damaged by falling branches. No casualties were reported.

More than 500 workers were deployed to clear the water, which was up to 30 centimetres deep on city roads, the report said.

The weather delayed scores of flights to and from Shanghai's Pudong and Hongqiao airports, Xinhua said, stranding thousands of passengers.

Torrential downpours have struck various parts of China during the annual summer rainy season.

Earlier this month Xinhua reported that the heavy rains had displaced more than 100,000 people in Sichuan province in the southwest.