By Renu Agal BBC News, Delhi

Ms Patkar is protesting against the raising the height of the dam

Ms Patkar and supporters are protesting in Delhi 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 the states of Gujarat and Madhya Pradesh, officials say.

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.

We have no assurances from the government. We can't die silently. Can we? Arundhati Roy

Mr Soz said some of the anti-dam protesters will also accompany the federal team which is due to leave on Thursday.

Ms Patkar drank a glass of lemon water after her condition worsened but said she would continue her hunger strike.

She is the creator of the Save Narmada Movement.

'No assurances'

Politicians, including former Prime Minister VP Singh, and many social activists have gathered at Delhi's Jantar Mantar landmark, the site of the protest, to express their solidarity with the anti-dam activists.

Activists are angry at a recent decision to raise the height of the dam from 110 to 121 metres.

Ms Roy had been jailed for her comments on the dam project

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.

India's Booker prize winner and activist Arundhati Roy told the BBC that the water resources minister "just said he will go to the Narmada Valley and see the rehabilitation work for himself but the construction is continuing, they are not stopping it."

"I was sent to jail for contempt of court. Why are these people who are doing mass contempt of court not being put behind bars?''

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.