Thousands of people in flood-ravaged southern India have begun the immense task of cleaning their homes and businesses.

Rains have been diminishing in parts of Kerala state, where floods and landslides have killed more than 200 people in less than two weeks and about 800,000 more have been forced into thousands of relief camps.

Torrential rains began on August 8 in Kerala in the midst of the annual monsoon season, eventually leaving much of the state partially submerged.

The Indian military also opened an air base on Monday to commercial flights to help bring in relief goods and fly out residents.

The first flight landed on Monday morning at the naval air station in the city of Kochi, where the commercial airport has been closed for nearly a week.

People are rescued from the floods
A volunteer rescues stranded people in Kerala (AP)

The Air India flight came from Bangalore in the nearby state of Karnataka, Suresh Prabhu, the minister of civil aviation, said on Twitter.

Other air bases in the region should open to commercial traffic soon, he said.

Thousands of people are taking shelter in small camps in the coastal town of Alappuzha. Many are in schools, but at least one is on the grounds of a mosque where Christians, Hindus and Muslims have all found food and a place to sleep.

With rains decreasing, the water has started receding in parts of Kerala but thousands of people remain cut off and in need of help.

Thousands of people have been saved by the state’s fishermen, many of whom headed into the floodwaters to help.

A policeman and a volunteer
An Indian policeman, left, and a volunteer carry essential supplies (AP)

On Monday, the state’s top official, Pinarayi Vijayan, announced the government would pay those fishermen about £40 for each day they helped and also pay for repairs for boats damaged during rescues.

Officials said it is the worst flooding in Kerala in a century, with rainfall in some areas well over double that of a typical monsoon season.

Relief supplies and donations have poured into Kerala from across India.

Officials have put initial storm damage estimates at nearly £2.35 billion.