In a late night swoop, the Delhi police have forcibly removed Narmada Bachao Andolan leader Medha Patkar from the spot of her indefinite hunger strike.
She is under observation at the capital's All India Institute of Medical Sciences.
The police have arrested 27 of her supporters on charges of rioting and preventing government servants from performing their duty.
The police maintain that Patkar, who has been leading the agitation for the resettlement rights of people displaced by the Sardar Sarovar Project, has not been arrested.
Doctors at AIIMS said the activist was in the Intensive Care Unit, she was conscious and her condition was stable.
Police sources said a first information report has been lodged against Patkar on charges of attempt to suicide. She is likely to be arrested after her health improves.
Since March 17, NBA activists have been staging protests in the capital against the Narmada Control Authority's decision to raise the height of the dam.
The NBA says the Sardar Sarovar Project has uprooted communities living in the Narmada Valley for the past many centuries.
The activists say nearly 35,000 families will be rendered homeless by the resultant rising waters if the height of the dam is increased.
Besides Patkar, Jamsinh Nargave and Bhagwatibai Patidar from the affected villages began an indefinite fast on March 29.
Patidar is continuing her hunger strike. The police tried to shift her to the hospital too, but NBA activists thwarted the attempt.
The police team, which tried to reason with the activists, retreated after the activists stopped them.
As the news about police taking away Patkar broke, a number of social activists arrived at the dharna site at Jantar Mantar to express solidarity with the NBA.
The activists say their agitation will continue and at least 10 people from the capital and three from the Narmada Valley have joined the hunger strike.
Jawaharlal Nehru University professor Kamal Mitra Chenoy and JNU Students Union president Mona Das have started their hunger strikes too.
The late night police action has failed to dampen the spirits of the protestors. They are continuing their agitation singing and beating percussive instruments.