Hundreds of people gathered at the Jantar Mantar on Sunday as Anna Hazare began his day-long fast to demand a stronger lokpal bill to fight corruption.
The agitation began with a short film screening on the whistleblowers who have been killed during their fight against corruption.
"Bharat Mata ki Jai...Vande Mataram," Hazare started the fast with patriotic slogans.
The 72-year-old is holding the fast to demand that parliament adopt the Jan Lokpal bill with a stronger whistle-blower protection provision.
Hazare said the government has failed to protect the whistleblowers in the country.
"The people who are fighting against corruption and have given their lives, the government is not doing anything to protect them," he told reporters ahead of the fast.
The Jantar Mantar is where Hazare first held a mass protest for a graft bill in April 2011.
Waving the tricolor and clad in khadi clothes, Hazare's supporters shouted slogans against corruption.
"We will succeed in bringing the Jan Lokpal bill. We hope to fight corruption. This movement is not just for day or so, it will go on," said Rajesh Singh, a 24-year-old student from Allahabad, Uttar Pradesh.
Donning 'Anna caps', supporters thronged the venue amid tight security arrangements by the Delhi Police.
Father of slain IPS officer Narendra Kumar, who was killed in Morena district of Madhya Pradesh is also likely to visit Jantar Mantar to meet Hazare. Kumar was killed while intercepting a tractor-trolley carrying illegally-mined stones.
Calling for a bigger movement, Hazare said Team Anna will travel across the country and tell people that the government's version of the bill is "useless".
"Twenty-five people who fought against corruption were murdered. We have been stressing on protection of whistleblowers through a law but the government is not ready to do it," Hazare said.
"There will be a bigger, countrywide movement against this. The government has not even investigated into the murder of people who stood against corruption," he added.