Floods sweeping Bangladesh marooned 500,000 people, killing at least 11, but appeared to be subsiding today.
Disaster management officials said about a quarter of the country was under water.
India opened flood gates on the common rivers, including the Brahmaputra, Meghna, Jamuna and Ganges, which is called the Padma in Bangladesh, sending torrents downstream to Bangladesh.
Many of Bangladesh's more than 150 rivers originate in the Himalayas and flow through India. Floods are a regular feature in the two countries during the July-September monsoon period and often they become treacherous, claiming thousands of lives.
The government and relief agencies were distributing food, medicine and other essentials among those taking refuge on high lands and buildings.
Officials could not give an exact number of people in the shelters but said some had left for their still partly flooded homes, hoping the water would recede soon.
A shortage of drinking water is the most serious problem facing millions of people in the flooded areas.
In early 1970s Bangladeshis installed tens of thousands of tube-wells for drinking water, trying to avoid diarrhea and other stomach ailments.
Bangladesh's worst floods in 1988 killed more than 3,500 people and washed away more than two million tons of rice crop, according to official estimates.
In early 1970s Bangladeshis installed tens of thousands of wells for drinking water, trying to avoid diarrhea and other stomach ailments.
But over the last few years Bangladesh health authorities have sealed off two-thirds of the country's wells, saying ground sources have been contaminated with harmful arsenic.
The government now advised Bangladesh's 130 million people to collect rain water and preserve it for drinking throughout the year as an inexpensive alternative.