Sunday night, however, AAP candidates and supporters were celebrating what their leader, 45-year-old former tax inspector Arvind Kerjiwal, called a "historic win".

In local assembly elections in Delhi, India's sprawling capital, the party won 28 out of 70 seats. Kejriwal himself beat the chief minster of the city, a veteran of the ruling Congress party who had dismissed the AAP as "not even on our radar" when it was founded a year ago, by a massive 27,000-vote margin. Congress was wiped out, reduced to eight seats.

"It's a remarkable achievement for a new party. There is a general dissatisfaction with political parties and we fought on basic issues – water, education, sanitation, security – which resonate," said Atishi Marlena, a historian who is a senior activist in the AAP.

The collapseof Congress support in Delhi was mirrored around India.

Though the opposition Bharatiya Janata Party was unable to clinch a majority in Delhi, elsewhere it won massive victories. The party wrested the state of Rajasthan from Congress, and held on to Chhattisgarh and Madhya Pradesh.

Narendra Modi, centre, Bharatiya Janata's prime minsterial candidate, and other party leaders before a meeting in Delhi on Sunday. Photograph: Ahmad Masood/Reuters

The elections are being viewed by analysts as the "semi-final" before the general election in late spring.

"The lineup will be the same next year and it's a meltdown for Congress. It's a real warning for them," Anil Padmanabhan, an analyst who writes for the newspaper Mint.

Congress has led the central government for two terms and is facing widespread anger about corruption, slowing growth and