The ceremony took place at an open ground, the Ramlila Maidan, rather than at the assembly's offices. Thousands of supporters gathered to watch.

Mr Kejriwal's Aam Aadmi Party (AAP) won 67 of 70 seats in the state assembly, trouncing both the mainstream parties.

The Bharatiya Janata Party (BJP), which won a landslide in last year's general election, was reduced to three seats.

It was a major setback for Prime Minister Narendra Modi.

Congress, historically the biggest party in Delhi, was wiped out.

Mr Kejriwal invited Prime Minister Narendra Modi to the ceremony but a spokesman for the chief minister-elect said Mr Modi had turned down the invitation.

The Ramlila Maidan is a huge ground in Delhi often used for political rallies, and Mr Kejriwal had invited all of Delhi to attend.

Mr Kejriwal was sworn in as chief minister at the same place in 2013, although he resigned after 49 days after failing to pass an anti-corruption bill.

The AAP was born out of an anti-corruption movement that swept India three years ago.

Mr Kejriwal has promised to end corruption and lower electricity and water bills.