Leading Indian environmentalist Medha Patkar, who has been on hunger strike in Delhi for eight days, has been arrested and taken to hospital.
Ms Patkar is protesting against raising the height of the dam
Ms Patkar and her supporters are protesting against the construction of a dam on the Narmada river.
The latest protest has been sparked off by the decision of the authorities to raise the height of the dam.
The dam is essential for drought-prone areas in Gujarat and Madhya Pradesh, officials say.
The police arrested Ms Patkar at the site of her protest and moved her to a hospital late on Wednesday night.
Senior police official Manish Agarwal told the Associated Press that Ms Patkar was arrested on charges of inciting unrest and hindering government officers from carrying out their duties.
Doctors at the hospital said her condition was "stable".
The police also arrested over 70 protestors, according to reports.
Ms Patkar's supporters said that the police had behaved roughly in "forcibly" taking away their leader.
"I can't believe the way in which the police behaved. They were brutal. Even if they wanted to take Medha to the hospital they could have done it in a more dignified manner," activist Shabnam Hashmi told NDTV news channel.
The federal Water Resources Minister Saifuddin Soz has said a federal team of four ministers will visit several areas in Gujarat, Madhya Pradesh and Maharashtra and review relief and rehabilitation for the 35,000 people displaced by the Sardar Sarovar Dam Project.
Mr Soz has said some of the anti-dam protesters will also accompany the federal team which is due to leave on Thursday.
Ms Patkar is the creator of the Save Narmada Movement.
Activists are angry at a recent decision to raise the height of the dam from 110 to 121 metres.
The protesters say the decision violates earlier Supreme Court rulings that prohibited further construction until the rehabilitation of displaced families is complete.
The court is due to hold a hearing in the case on 17 April.
The Sardar Sarovar project was initiated by India's first Prime Minister, Jawaharlal Nehru, in the 1950s. It has been delayed by longstanding legal disputes and protests.