At least 35 people were killed after a pilgrim bus swerved off the road and fell into a canal near the town of Parasi, 160 km (99 miles) south-west of Kathmandu, local police said on Sunday.
The bus was taking the pilgrims from the Indian state of Uttar Pradesh to the Hindu pilgrimage site at Triveni near the Indian border to attend the Bolbam religious festivity.
The bodies of 24 men, 10 women and a child have been recovered while more than 12 persons have been injured in the accident, the police said.
The bus was overcrowded, with some pilgrims riding on the roof.
The Nepal army and police are carrying out rescue work at the site of the tragedy. The number of casualties could increase further, the police said.
In another accident in India, at least 15 Hindu pilgrims were killed and another 17 injured after a passenger bus fell into a deep gorge in India-controlled Kashmir, Xinhua news agency reported, citing local officials.
The accident occurred on Saturday night near Digdol in the Ramban district.
"All the people on board were Hindu pilgrims," a police official said.
