With rivers bursting their banks along the fertile plains south of the Himalayas, India ordered the army to help evacuate people from some of the worst-hit areas.
"I have not seen such flooding in the last 24 years. It’s a sheet of water everywhere," said Santosh Mishra, a resident of Gonda district in Uttar Pradesh. "There are no signs of houses, temples or trees," he told the local Sahara Samay television channel.
Some14 million people in India and five million in Bangladesh have been displaced or marooned by the flooding, according to government figures. At least 132 people have died in recent days because of the floods in India and 46 more in Bangladesh.
"The situation is grim," said Bhumidhar Barman, a minister in the Assam state Government.
The monsoon season in South Asia runs from June to September and is vital to agriculture.
But the monsoons are dangerous; last year more than 1000 people died, most by drowning, landslides, house collapses or electrocution. In New Delhi, India’s Meteorological Department said unusual monsoon patterns this year had led to heavier rains. "We’ve been getting constant rainfall in these areas for nearly 20 days," said department spokesman BP Yadav.
Some 100,000 displaced people were staying in government relief camps in Assam, while hundreds of thousands more sought shelter on higher ground, setting up makeshift dwellings. Millions of people have been cut off from the rest of the country.
Medical teams were trying to visit regions by boat to ensure there were no outbreaks of water-borne diseases such as cholera.
In Uttar Pradesh, the army was called in to help evacuate people from 500 villages under water, said Diwakar Tripathi, a senior government official. Huge amounts of crops had been destroyed.