NEW DELHI - The ruling Congress party was routed in state elections, including in its stronghold of Delhi, in what was seen as a test for next year's general election.
Congress lost to its main rival Bharatiya Janata Party (BJP) in the states of Delhi and Rajasthan that it had held and failed to wrest Madhya Pradesh from the BJP.
The BJP was ahead in Chhattisgarh, which it rules and where the Congress had been hoping to ride to victory on a sympathy wave after its top leadership there was gunned down by Maoist rebels while on the campaign trail.
Polls were held last month and this month but counting took place only on Sunday.
Admitting defeat, Congress president Sonia Gandhi said: "In all humility, we congratulate all our opponents for winning the elections."
She promised a course correction. "Naturally this result calls for deep introspection. Of course there were a number of reasons for the defeat. I know many people are unhappy," she said.
The BJP announced it would form a government in all four states. The results of a fifth state, Mizoram, are expected today.
In Delhi, while celebrations broke out in the BJP headquarters, the headline-grabber was political newcomer Aam Aadmi party (AAP), which won 27 of the 70 assembly seats, rare for a new entrant in Indian politics. The anti-corruption party was formed only in November last year.
The BJP, however, edged past the AAP with 31 seats, falling a few seats short of a majority but with enough to form a minority government.
The Delhi results ended the 15-year dominance of the Congress party, with three-term chief minister Sheila Dikshit accepting defeat and putting in her resignation long before the final tallies were announced.
The Congress, which won 43 of the 70 seats in 2008, took only nine seats this time round.
Ms Dikshit even lost her constituency of New Delhi to AAP leader Arvind Kejriwal, an income tax officer turned politician.
"It is a wake-up call for the Congress... There is this mood of frustration and unhappiness with the government," said Professor Sandeep Shastri of Jain University.
Public anger has been rising over the Congress' failure to stem the rising prices of food items and fuel. The party was also beset by several corruption allegations including in the allocation of coal blocks and telecoms licences.
The sweeping wins of the Hindu nationalist BJP are expected to be a boost for its general election campaign leader and prime ministerial candidate Narendra Modi, but a setback for his rival, Congress vice-president Rahul Gandhi. Both men campaigned in all the four states.
The BJP predictably called its wins an opener for the general election, which must be held in six months. But this assessment is dismissed by Mr Gandhi who said his party had the "ability to transform itself".
Still, a jubilant Ms Vasundhara Raje, the Chief Minister-designate of Rajasthan, said: "I think this is the semi-final and in six months you will see the finals."
The AAP also expressed its intention of fighting the parliamentary elections on the back of its massive showing in Delhi.
But it was Jammu and Kashmir Chief Minister Omar Abdullah who summed up the political mood in the country in a tweet. "Notes to self for #2014: never underestimate the underdog/newcomer with a fresh face and message," he posted on social networking site Twitter.
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