The Kareh, Bagmati and Kamala Balan rivers in the state of Bihar have breached their embankments and flooded vast areas with an aggregate population of about 6 million, washing away crops and destroying communications. A lack of drinking water and medicines has been reported in the flood-ravaged districts.
The Brahmaputra, a major river in the state of Assam has flooded hundreds of villages with a total population of 4.4 million.
The situation remains critical in Uttar Pradesh, India's most populated state, where 22 people have been killed and seven reported missing after a rescue boat capsized.
Rains also caused landslides that blocked roads to the popular pilgrimage sites of Badrinath, Hemkund and Yamunotri in the Himalayas.
Lalu Prasad, the country's minister of railways, conducted an aerial survey of the affected regions by helicopter. He said he would report on the disastrous situation to Indian Prime Minister Manmohan Singh and Sonia Gandhi, the leader of the ruling coalition.
Weathermen said the flood situation would remain grim in the majority of the hardest-hit regions for the next two days.
Heavy rains are wreaking havoc in the neighboring Kingdom of Nepal, with the death toll reaching 86.
Bangladesh, a low-lying country in the delta of the Ganges and Padma, has also been inundated.
