A tunnel under construction at a hydropower project in India’s northern state of Uttarakhand collapsed overnight, killing at least seven workers, officials said Friday.

The incident occurred at the Vishnugad-Pipalkoti hydroelectric project in Chamoli district late Thursday night when a sudden rush of water and debris entered the tunnel, according to top district official Gaurav Kumar.

Of the 22 individuals working inside the tunnel at the time, 12 have been rescued alive. Three additional workers are still missing, Uttarakhand state Chief Minister Pushkar Singh Dhami told reporters.

Rescue teams from the National Disaster Response Force, the state Disaster Response Force, the Indo-Tibetan Border Police, and fire services are working to locate the remaining missing workers. Commander of the National Disaster Response Force team Amrit Lal Meena described the challenging conditions, noting the presence of significant water inside and seeping from the tunnel walls, with the water level steadily increasing.

Construction accidents are not uncommon in India, where rapid infrastructure development frequently intersects with geological vulnerabilities, lapses in construction practices, severe weather, and inadequate safety standards.

The Himalayan region, in particular, presents heightened risks for tunnel projects due to its fragile mountain terrain, seismic activity, and unpredictable underground conditions. In February, an explosion in a coal mine in the neighboring state of Meghalaya resulted in the deaths of at least 18 workers. In 2023, a tunnel section in northern Uttarakhand collapsed, trapping 41 workers for 17 days before their eventual rescue.