A controversial dam project in India has started generating power in the western state of Gujarat.
The dam project was initiated in the 1950s
The $7bn project on the Narmada river aims to resolve power and water shortages in central and western India.
The project was initiated by India's first prime minister, Jawaharlal Nehru, in the 1950s but opposition from campaigners led to long legal battles.
Critics say it has displaced tens of thousands of villagers who have not been adequately compensated.
The Sardar Sarovar dam is the centrepiece of a network of reservoirs and canals along one of India's longest rivers.
Its supporters say it will help irrigate millions of acres of farmland and provide drinking water to some 20 million people in an area that is prone to drought.
Inaugurating the dam, Gujarat chief minister Narendra Modi said it would bring 1450mw of hydro-electricity to the region.
He said the dam would benefit the states of Gujarat, Rajasthan, Madhya Pradesh and Maharashtra.
Water from the dam would irrigate more than 2 million hectares of land in Gujarat and Rajasthan.
Four former chief ministers of Gujarat, all of them members of the Congress party which is in opposition in the state, boycotted the function at the dam site at Kevadia in Narmada district in the east of the state.
They said very little progress had been made in laying the canal network that would provide water to the millions residing in parched areas of Saurashtra and Kutch in Gujarat.
The concrete work on the Sardar Sarovar project was completed recently after the Indian Supreme Court had allowed its height to be raised to 121.92 metres.
The project has been shrouded in controversy.
Environmental activists have led a lengthy and visible campaign against it, saying it has displaced tens of thousands of poor tribal villagers who have been poorly resettled and badly compensated.
They say it will also destroy the rural economy and the livelihoods of those who live in its shadow.