On Day 10 of his fast, Anna Hazare's health was declared "somewhat stable" by doctors on Thursday evening.
Hazare looked feeble and admitted to feeling weak in a 20-minute speech on Thursday afternoon.
"I can go on but due to weakness, I am ending my speech," he told thousands supporting him at Ramlila Maidan.His blood pressure and pulse are being monitored every hour.
Three ambulances are stationed at the venue to rush Hazare to the hospital, if needed.
"Annaji's blood test results are stable, but there is still a cause of concern for us, as he has not eaten anything for the past 10 days. My team of doctors will keep a close watch on him though the night," said Dr Naresh Trehan, chairman of Medanta - the Medicity.
"He should increase his water intake and not exert himself. He can do without a drip as of now," said a doctor treating him.
The social activist started the fast on August 16.