Soldiers and aid workers scrambled on September 2 rushed to reach hundreds of thousands of people still stranded on rooftops, trees and outcrops of dry land more than two weeks after monsoon rains had caused the Kosi River to burst its banks and turn hundreds of square kilometres of Bihar state into a giant lake.

The army have sent more than 5,000 soldiers to join the rescue effort, while officials said that more than half of the 1.2 million stranded had been rescued. The death toll is estimated to range from dozens to thousands.

Relief efforts were haphazard amid the chaos and some areas were cut off, posing fresh challenges to rescuers.

Officials say that the flooding is expected to continue until November, when the last of the monsoon rains will start to taper off.