Fifteen people were electrocuted to death and several injured in an accident at a power transformer at a Namami Gange project site on the banks of the Alaknanda river in Chamoli district, an official said on Wednesday.
The dead included three police inspectors and three home guards, the official said.
The injured were admitted at the district hospital.
Chief Minister Pushkar Singh Dhami expressed grief over the loss of lives and said a magisterial inquiry has been ordered.