Tens of thousands of people wearing “I am the common man” caps cheered as a popular anti-corruption crusader was sworn in as the city’s chief minister in a park Saturday.

Arvind Kejriwal, a 45-year-old taxman turned activist turned politician, vowed to end corruption in the Indian capital, cut electricity bills by half and provide households with free water.

“We do not have all the wisdom, all the answers. We do not have a magic wand and cannot solve all the city’s problems in one day,” Kejriwal told the crowd after he was sworn in. “But this government will not be run by ministers and officials. It will be run by the 15 million people of this city in a participatory manner.”

His new Aam Aadmi Party (AAP), or the Common Man’s Party, was formed more than a year ago by anti-corruption activists who had led national protests against rising graft scandals. Kejriwal took his oath on the same sprawling grounds where the activists began their protests with a hunger strike in 2011.

The party, which has harnessed public anger against corruption, soaring prices and elitist politicians, came in second in local elections this month, pushing the incumbent Congress Party government in the city to third place. The Hindu nationalist Bharatiya Janata Party won the largest number of seats but fell short of a majority. Congress has said it will extend its support to help AAP secure a majority in the assembly. But the two parties are bitter rivals, and some AAP critics have questioned their party’s decision to accept the offer.

The new government will face its first test on the floor of the Delhi legislative assembly in a week when Congress Party members will be asked to show in a vote whether they support the AAP.

Kejriwal’s speech Saturday was replete with idealistic rhetoric.

“From now on, if any official asks you for a bribe, say yes, you will pay,” he said as the audience clapped. “And then alert us on our help line, and we will catch them red-handed.”

Kejriwal promised regular neighborhood meetings and said that decisions about infrastructure will be made after consultations with the people.

“Long live the common man!” shouted some in the crowd in the park. Others wielded brooms, the party symbol, in one hand and cellphone cameras in the other. Some sang patriotic songs and danced.

“Gone are the days of the huge distance between the voters and their leaders, no more long lines outside government offices to get services, no more bribes,” said Mohammad Zahid, a 38-year-old supporter who runs a shop that dyes saris and scarves. “This will be our government, people’s government.”

Kejriwal, his colleagues and their families traveled by subway to reach the park, a symbolic departure from the traditional cavalcade of cars most elected politicians in India travel in, often blocking public traffic. He has also declined police security cordons, official cars with flashing red-beacon lights and a government bungalow.

“This is a completely different grammar of political power on display. It upends all our traditional notions of how elections are fought and won and how the elected conduct themselves,” said Santosh Desai, a social commentator and newspaper columnist.

“This may be a brief, mad moment in Indian politics, but this is a moment we must savor. But there is a deeper, larger message here that the other parties will have to pay attention to in the national elections next year.”

The Indian media reported this week that some government files were being hurriedly shredded and burned by officials who fear that Kejriwal’s team will scan the records for evidence of wrongdoing by previous governments and investigate the corrupt.

Some economists have said the new party’s populist promises of electricity and water may cost the taxpayers.

“The problem is that the average voter, with perhaps a fondness for everything ‘free’, does not realize the inherent trade-offs,” economist Bibek Debroy wrote last week in the Economic Times. “When seeds of socialism are sown, it is future generations that suffer the weeds.”