New Delhi (BBN)- India's Prime Minister Narendra Modi has admitted defeat in Delhi state elections after results showed anti-corruption campaigner Arvind Kejriwal's party heading for a landslide win.
Mr Modi congratulated Mr Kejriwal and promised him complete support, reports BBC.
Mr Kejriwal's anti-corruption Aam Aadmi Party (AAP) is leading in 63 of the 70 seats, while Mr Modi's Bharatiya Janata Party is ahead in only four seats.
The AAP is led by former tax inspector and activist Arvind Kejriwal.
Correspondents say his win would mark a remarkable comeback for the campaigner.
Mr Kejriwal's party was routed by the BJP in May's general elections, months after the AAP made a spectacular debut in the 2013 Delhi elections.
On the other hand, Mr Modi has enjoyed huge popularity since taking office last year, winning a string of local elections and wooing international investors and world leaders, and the BJP's defeat in Delhi is his first setback.
Mr Kejriwal told cheering party supporters on Tuesday that the "people of Delhi have achieved something spectacular".
"With the help of people, we will make Delhi a city which both poor and rich will feel proud of," he said.
The BJP's campaign was essentially anti-AAP and the party leaders often criticised Mr Kejriwal at their rallies and road shows.
Mr Kerjiwal, meanwhile, conducted an energetic campaign which proved popular with working class and underprivileged voters who make up 60% of Delhi's population.
Mr Modi's Bharatiya Janata Party (BJP) fielded former policewoman Kiran Bedi as its candidate for chief minister.
"We never expected that the results would be so depressing. We never expected that we would suffer such a setback. It is certainly not our day today," BJP leader Praveen Shankar Kapoor told BBC Hindi.
The Congress party, which ran the Indian capital for 15 years until 2013, has suffered a complete rout and is not even leading in one seat.
Delhi has been without a government since Mr Kejriwal resigned last February as chief minister, angered that his anti-corruption bill was blocked.
Since then the state has been governed directly by the federal authorities.
The atmosphere around the Aam Aadmi Party (AAP) is electrifying.
As results showed the anti-corruption party steaming ahead, supporters began discussing the formation of the new government.
They say their victory "will be a reinforcement of the common man's choices".
"If people feel 2014 was the year of the Modi wave, this will be the year of an AAP sweep," Rajesh Kumar Arya, a supporter, said.
Even though the actual results are a few hours away, sweets have begun arriving in homes in the neighbourhood for the celebrations and AAP supporters are setting off fireworks and singing songs.
The BJP supporters I spoke to said they felt dejected by a few crucial decisions the party took immediately before the polls, including the announcement of the "outsider" Kiran Bedi as the chief ministerial candidate.
Ms Bedi and Mr Kejriwal worked together during the anti-corruption campaign led by social activist Anna Hazare, but the two have since developed an intense rivalry.
During weeks of hectic campaigning in Delhi, both candidates promised to bring in good governance, end corruption and make Delhi safe for women.
In the previous Delhi election held in December 2013, the BJP won the most seats but fell short of a majority, leaving the AAP - which came second - to form a coalition with the Congress party.
But Mr Kejriwal resigned on 14 February, after 49 days in office, when opposition politicians blocked a bill that would have created an independent body with the power to investigate politicians and civil servants suspected of corruption.
BBN/SK/AD-10Feb15-1:00pm (BST)