Officials said two bodies have been recovered thus far. The dead and missing were part of a group of 60 students and teachers of Vignana Jyothi Institute of Engineering and Technology in Hyderabad, India, on their way to the resort town of Manali for a holiday.
They were taking photographs on the banks of the river when a discharge from a reservoir two kilometers (1.2 miles) upstream caused a surge in the river's water level.
District magistrate Pankaj Rai said one body was recovered from another dam, 20 kilometers (12 miles) downstream of the incident, whose floodgates were closed after the water surge.
A case of negligence, against the engineer of the state-run hydroelectric dam project, has been lodged. Local residents blocked nearby highways after the incident to call attention to their contention the hydroelectric power project routinely releases water from its dams without warning.
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