NEW DELHI — The voters of Delhi face the terrifying certainty that their most fervent wish will be granted.

In November, they will have the opportunity to bring to power the kind of person they have claimed for years they want to see in politics: an incorruptible man who is good at math, who has not been marinated in politics. An indignant man with genuinely black hair who does not wear the starched white clothes that Indians recognize as the costume of corruption, but instead appears in public in a modest cotton shirt that he never tucks into his modest trousers and with a cap that has a reprimand to politicians written on it. An engineer who once cleared the toughest engineering entrance exam in the country. A man who could have grown rich had he pursued a management degree or written terrible books, which elite Indian engineers do successfully, but who instead chose to enter public life vowing to disrupt political corruption and who became one of the key activists who persuaded the Indian government to pass an extraordinary act granting citizens the right of access to public documents.

Arvind Kejriwal and his Aam Aadmi Party will debut in electoral politics this November and contest all 70 seats in the Delhi assembly elections. On trial will be the people of Delhi themselves, and a beloved Indian hypothesis that they deserve better than rotten politicians. If virtue alone were to decide elections in India, the two major parties in Delhi, the governing Indian National Congress and the Bharatiya Janata Party, would not stand a chance against Mr. Kejriwal.

“We will form the government,” Mr. Kejriwal told me on Saturday when I interviewed him before a small audience that had come to listen to him in a lakeside restaurant. He said this without any facial twitches or the high passion of delusion, but as a matter of fact. He said that in most of Delhi where the poor and the lower-middle class live there is no water supply for days and no electricity for hours every day. Politicians from both the Congress party and the B.J.P. control “cartels,” he said, that own water tankers, and it is in their interest to ensure that people face water shortages. According to Mr. Kejriwal, there is “an undercurrent” in Delhi against established political parties that was perceptible only to the poor, and to him. “People are fed up,” he said.