India's ruling Congress-led alliance was set to return to power after taking a commanding lead on Saturday in vote counting for the marathon 15th Lok Sabha elections.
The Election Commission website showed the Congress UPA alliance with a lead of around 80 seats over the main opposition bloc headed by the Hindu nationalist Bharatiya Janata Party (BJP).
With counting underway in 502 of the Parliament's 543 directly elected seats, the UPA was leading in 229, while the BJP alliance had the edge in just 155.
While projections showed the Congress grouping still falling short of the 272 seats required for an absolute majority, the margin of its lead gave it an insurmountable claim to form the next government.
"It is a decisive vote for the Congress," said party spokesman Abhishek Manu Singhvi, as wild celebrations broke out at the Congress Party headquarters in New Delhi.
Party supporters banged drums and danced in the street, holding portraits of Congress president Sonia Gandhi and Prime Minister Manmohan Singh.
"Manmohan Singh will be the Prime Minister once more," announced delighted cabinet minister Oscar Fernandes.
The mood at the BJP headquarters was, by contrast, subdued as the counting results rolled in.
"It has to be analysed, but it is disappointing I agree," said senior BJP leader Venkaiah Naidu.
The apparent margin of victory was much higher than that predicted by exit polls, which had suggested only a handful of seats would separate the two main political groups.
Congress was also clearly emerging as the single largest party in parliament, leading in 180 seats, against 90 for the BJP.
"The trends are very positive," said Congress leader Ambika Soni. "We want to thank the people of India who have shown faith in the Congress party."
This election has come at a pivotal time for India and its 714-million strong electorate.
After five successive years of near-double digit growth that lent the country the international clout it has long sought, the economy has been badly hit by the global downturn.
And there are major security concerns over growing instability in South Asia, particularly in arch-rival Pakistan, with
whom relations plunged to a new low following last year's bloody militant attack on Mumbai.
The unexpectedly strong vote for the ruling alliance will go some way to allaying the concerns off those who expected a tighter race that would have thrown up a shaky patchwork coalition.
The Congress will still need more allies to command a parliamentary majority, but a strong lead over the BJP alliance will make its task far easier.
Congress has spent much off the past week making overtures to the party's former communist allies, who quit the coalition last year in protest at a nuclear deal with the United States.
Ambika Soni said Congress leaders and their allies would meet later in the day to discuss how they would go about building the support they need to govern India's 1.1 billion people.
According to the constitution, a new government must be formed by June 2.
BJP concedes defeat
Virtually conceding defeat in the Lok Sabha elections, the BJP today said the trends were "disappointing" and not on expected lines.
"Trends are not on expected lines. It is little disappointing....We concede UPA is ahead," BJP spokesperson Balbir Punj said as trends indicated that the UPA was racing ahead.
He said the party's parliamentary board will meet to analyse what went wrong.
Punj said the trends were also not expected lines in the states of West Bengal, Andhra Pradesh, Tamil Nadu and Kerala for Third Front.
Admitting that Congress "seems to have the upper hand", another BJP leader Venkaiah Naidu said "as of now UPA is leading. We are lagging behind."
Asked what went wrong, Naidu said "that has to be analysed. It is disappointing, I do agree".