One of India's most popular yoga gurus is leading followers in what is being called a fast to the death, part of a populist campaign to fight corruption.

Swami Baba Ramdev began his fast in front of thousands of supporters in New Delhi Saturday, promising India would be saved. He told them “nothing is impossible” and vowed they would not be defeated.

Ramdev's demands include a return of so-called black money, cash stashed in foreign bank accounts and used to pay bribes. He also is calling for the execution of corrupt government officials.

Critics charge Ramdev has ties to right-wing Hindu groups and question his sincerity, arguing he lives lavishly with money from his multi-million dollar business ventures. But his call to end widespread corruption appears to be resonating in a country still reeling from a $39 billion telecom scandal and a scandal-plagued Commonwealth Games that have seen some ministers end up in jail.

Earlier Saturday, Prime Minister Manmohan Singh sent four government ministers to meet with Ramdev in an attempt to stop his protest.

Ramdev refused to comment on what was said during the meeting but told supporters he would not be deterred.

Ramdev's supporters joined in mass fasting Saturday in Mumbai and other states across India.