A stunning performance by an upstart anti-corruption party helped topple India’s ruling Congress in elections to New Delhi’s state assembly Sunday, only months before the country goes to the polls.Congress, in power at national level for a decade, was also in danger of losing control of three other state assemblies up for grabs in Sunday’s vote count, in a devastating blow ahead of next year’s general election. “I would like to congratulate the people of Delhi for starting a trend of honest politics,” said Arvind Kejriwal, leader of the fledgling Aam Aadmi Party (Common People’s Party), after he unseated the capital’s chief minister Sheila Dikshit in her own constituency.Kejriwal, who only launched his party a year ago, said his movement “will not be limited to Delhi alone, but will spread across the entire country and will be successful in getting rid of corruption and inflation”. A shell-shocked Dikshit said she would “analyse later what went wrong”. “All I can say is that the people of Delhi have taken a decision which we respect,” she added. Aam Aadmi, which tapped into widespread anger over corruption under Congress Prime Minister Manmohan Singh, even managed to deprive the main Hindu nationalist opposition Bharatiya Janata Party (BJP) of a majority. With just one result still to be called, the BJP had won 31 of the 70 Delhi assembly seats while Aam Aadmi had captured 27. Congress trailed in third with just eight, down from 43.The BJP also won by a landslide in the states of Rajasthan and Madhya Pradesh, although it had only a slender lead over Congress in restive Chhattisgarh with around a third of seats still to be declared. The elections for the four states have been held at different points over recent weeks but the counting had been postponed until Sunday.  Votes will be counted in the remote Congress-ruled state of Mizoram on Monday.Aam Aadmi only fielded candidates in New Delhi but the results will increase expectations that it will run nationwide when the world’s largest democracy holds its general election, by next May at the latest.  “We have succeeded in altering the political discourse of the elections,” Atishi Marlena, one of Kejriwal’s top lieutenants, told the NDTV network. Triumphant Aam Aadmi supporters at party headquarters waved brooms - the symbol of its pledge to clean up politics.BJP activists celebrated in Delhi, Madhya Pradesh and Rajasthan, dancing to the beat of drums, bursting firecrackers and waving the party’s lotus symbol.The assembly votes mark the last major test before Congress and the BJP, fielding hardliner Narendra Modi as its candidate for the premiership, face off in the general election. Rahul Gandhi, who is expected to lead the Congress general election campaign, said the party understood voters’ anger and in particular would learn lessons from Aam Aadmi’s strong showing. “It’s our duty to listen to you... I want to tell you that we have heard what you have said,” said the 43-year-old, whose father, grandmother and great-grandfather have all served as prime minister.“The Congress party has the ability to transform itself, has the ability to stand up to the expectations of the people of this country. The Congress party is going to do that.”  Analyst Amulya Ganguli said the chickens had come home to roost for Congress after economic growth slowed to around five percent and following a series of corruption scandals - including surrounding the chaotic 2010 Commonwealth Games in Delhi. “Had they managed to keep the economy buoyant, then that would have at least been a buffer against the numerous scams during their time,” he said. The elections are also a test for Modi, who is popular with middle-class voters but whose reputation was tarnished by deadly anti-Muslim riots that occurred on his watch as Gujarat chief minister in 2002.Modi, 63, voiced delight on Twitter, congratulating the party’s leaders in Madhya Pradesh and Rajasthan for their “wonderful performance” and “historic victory”.