This article is more than 6 years old

This article is more than 6 years old

Outside the headquarters of the Aam Admi (Common Man) party in central Delhi on Sunday night, hawkers sold poppadoms, bored police watched from squad cars and a crowd of excited young people sang songs dating back to the days of India's independence movement.

"This is what we do best in this country: non-violent revolution," said Shehshan Partak, a 25-year-old engineer and activist for Aam Admi (AAP). "And this is a revolution."

The claim is exaggerated but perhaps not entirely unjustified. The results of recent elections in Delhi and three other Indian states, released on Sunday, indicate that change is imminent in the in the world's biggest democracy. A general election is less than six months away.

On 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 collapse of 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 soaring prices of everyday items.

Congress politicians played down the significance of the defeats. Jyotiraditya Scindia, a Congress party minister, said the state elections are "a mandate on state-level issues … not a mandate on any person's leadership or for 2014".

The coming election is being seen as a contest between Congress's Rahul Gandhi, the scion of the Nehru-Gandhi political dynasty, and Narendra Modi, the chief minister of Gujarat and the BJP's declared prime ministerial candidate. Both campaigned for the recent polls.

Modi, three times chief minister of Gujarat, is a Hindu nationalist whose reputation has been tarnished by allegations that he failed to protect Muslims during sectarian rioting in Gujarat in 2002. The 63-year-old is, however, popular with the business community and among many urban voters.

Analysts were split over how far Modi's vigorous campaigning of recent months had contributed to the BJP's strong showing.

"It's impossible to quantify a Modi factor in state elections but it's a very good result for the BJP and gives them a real springboard for the contest next spring," said Swapan Dasgupta, a political analyst.

Vinod Sharma, political editor of the Hindustan Times, said that the defeats for Congress were less to do with Modi and more a display of local dissatisfaction with the national Congress-led coalition government.

The Congress party's poor performance in the state assembly elections will lead to further questioning of Gandhi's leadership abilities.

Sonia Gandhi, the president of the Congress party watches her son Rahul, the vice-president address the media as the party's results disappointing results came in. Photograph: Reuters

Some analysts have contrasted Gandhi's stress on the Congress-led government's massive expansion of welfare programmes with Modi's more "aspirational" messages aimed at India's youthful population. At least 120m first voters are estimated to be eligible to vote next year.

Gandhi said on Sunday that both mainstream parties were "thinking about politics in a traditional way". Congress would learn from the AAP's success and "involve people across the country in ways you cannot imagine right now", the 43-year-old former management consultant told reporters.

His mother, Sonia Gandhi, said the party would "accept the verdict of the people in all humility".

India's fragmented political landscape makes forthcoming national elections hard to predict, however. Historically, strong state results have not always translated into success in national elections.

And though last night AAP activists at its campaign headquarters said it would now change "whole India", Dasgupta said that the AAP would have great difficulty expanding beyond the capital.

"Kejriwal was able to seize the anti-Congress mood and the moribund state of the local BJP gave them an opportunity. But its impact will be limited to one state," he said.

The Indian economy has boomed in recent decades but the wealth is poorly distributed and a weak state is unable to deliver basic services and security to the estimated 15 million inhabitants of the country's capital.

The AAP's support is strongest among the lower middle classes, who do not have the resources to pay for private substitutes for poor public services such as transport or education. As urban populations swell in India so this constituency has grown.

Analysts also pointed out that traditional Congress support from those at the bottom of India's caste system, the tenacious social hierarchy, appeared to be absent.

The AAP has argued that a new style of politics should ignore factors such as caste and focus on delivery of basic services, honest administration and transparency.

"I voted for Kejriwal because all the others are thieves. They tell us they will help us when they want our votes and then we never hear or see them again," said Mohan Lal, a 42-yea- old cobbler in west Delhi.

Marlena, the activist who is also one of the AAP's key policymakers, said the party was part of a broader, worldwide phenomenon, such as the political groups "coming out of people's movements" in Europe and the Middle East. The AAP has its roots in an apolitical protest movement against the endemic corruption in India.

"We think there is a political space. Democracy has ignored the common people for too long," she said.