The 260m high dam on the Bhagirati river – a tributary of the Ganga, approximately 300km north of New Delhi, is located in a highly seismic area near the Himalayas prone to landslide activity. However, no seismic activity was reported at the time of the accident.The stability of the dam and the surrounding area has been investigated by a number of high powered panels, who found the design of the dam to be satisfactory under extreme seismic loading conditions. Environmental groups and activists have opposed the project since it was first proposed in 1972. In 1992 the groups filed action alleging that the required mandatory clearances for the project had not been obtained. After many years of legal action by the petitioners, the Indian Supreme Court ruled in 2003 that there was no material on record to show that statutory environmental conditions had not been complied with, and ruled in favour of the developers, Tehri Development Corporation – a joint venture of the Government of India and the state of Uttaranchal. When it is completed, Tehri Dam will be the fifth highest rockfill dam in the world with the potential to produce 2400MW of power. The first stage of the hydro power plant consists of four units of 250MW capacity.