Twenty-nine labourers were washed away early Thursday morning in flash floods in Kailashu river at Akrouli village in Udhampur Nagar district in the state of Uttaranchal.
Thirty labourers, sleeping in an open area in Akrouli, sought refuge in a tractor trolley to save themselves from the rushing waters, Udhampur Nagar District Magistrate Sunderlal Munyal said.
The strong currents, however, washed away the trolley, taking with it 29 labourers. One person managed to swim to safety.
Indian Air Force helicopters have been pressed into service for rescue and relief operations, Inspector General (Kumaon Range) Vijay Raghav Pant said.
Divers have also been asked to fish out the bodies, he said.