By Subir Bhaumik
BBC News, Calcutta
At least seven people have died in flash floods in India's north-eastern state of Assam, officials said.
Parts of the state have been cut off (Pics: Subhamoy Bhattacharya)
The floods followed heavy rains over the past three days and officials say more than a million people have been displaced.
The Brahmaputra, the region's biggest river, and its tributaries are flowing above danger level, they said.
Flood waters have submerged parts of the highway which connects the state with the rest of India.
Eyewitnesses say thousands of trucks and buses carrying supplies and passengers are stranded on the highway.
A million people have been displaced by the floods
"I think we are stuck here for a few days until the rivers recede," truck driver Kikar Singh, who is transporting wheat to Assam, said.
His vehicle is stuck in waist-deep water on the national highway near Tihu.
Motorists say an alternate route meant for smaller vehicles, through the hills of the neighbouring state of Meghalaya, is not safe either.
"This route is very dangerous. The road has been washed away in several places and is submerged in many areas. My car was nearly swept away, this was a nightmare drive, I was very tense," schoolteacher Smita Mishra, who travelled on the road said.
The only rail link between Assam and the rest of the country is still intact but only just.
Railway officials say the condition of some of the bridges needed extensive repairs after last month's floods - but before the repairs could be completed, the floods were back again.
The world's largest river island, Majuli, is facing a split down the middle due to extensive erosion and floods.
One of the embankments that protects this world heritage site from the Brahmaputra river is on the verge of collapse.
This is the third time floods have ravaged Assam this year.
The damage to roads, bridges and rail tracks has been extensive - estimated by the Assam government at around $366 million (1.5 billion rupees).
And the loss to standing crops and village houses has been substantial - around $245 million (one billion rupees), according to Assam's government. "But before we could recover from the two earlier floods, we have been hit by a third wave," Assam government spokesman, Dinesh Deka, said.
Assam has been spared the usual heavy floods in the last two years but this year's losses would be one of the heaviest in recent memory, Mr Deka said.
Millions have been affected by recent floods across parts of South Asia. Hundreds of people have died.