By Seema Chishti
BBC News, Delhi
India's Supreme Court has ruled that work on the controversial Sardar Sarovar dam on the Narmada river in central India can continue.
The dam project began in the 1950s
The court refused to stop the height of the dam from being raised, as demanded by campaigners, and said the government must decide the dam height by 6 July.
The court appointed 40 teams of observers to visit affected areas.
Thousands have been displaced by the project which will provide dry areas of Gujarat and Madhya Pradesh with water.
Activists of the Save Narmada Movement say the state governments have failed to provide adequate relief and compensation to those displaced by the dam.
They went to court, saying raising the height of the dam would make the situation worse.
In recent weeks, high-profile protests by Bollywood stars and writers have highlighted the issue - as has an 18-day hunger strike by the leader of the Save Narmada Movement, Medha Patkar.
Gujarat Chief Minister Narendra Modi also went on a 51-hour symbolic hunger strike against the anti-dam campaigners.