Aam Aadmi Party chief Arvind Kejriwal
Arvind Kejriwal, self-declared anarchist, could return to lead Delhi, according to exit polls.
An aggregate of seven exit polls showed Mr Kejriwal's Aam Aadmi Party (AAP) accumulating 42 seats, which would enable it to comfortably form the government (polls: Nielsen, C-Voter, Cicero, News Nation, Axis APM, Today's Chanakya, Data Mineria).
In a tweet, Mr Kejriwal thanked Delhi and said it had "rejected the politics of caste and religion."
Polls have in the past proven deeply inaccurate. Results will be counted on Tuesday.
"This is based on data till 3 pm. Let us not accept it as final," cautioned Kiran Bedi, who is running as the BJP's presumptive Chief Minister against Mr Kejriwal.
If AAP wins, it will mark the first major setback for Prime Minister Narendra Modi in the eight months since he won the national election with a massive mandate.
67 per cent of the capital voted today, a turnout higher than for last year's national election, or the assembly election a year ago, which saw Mr Kejriwal taking office for a 49-day term with a minority government.
If the exit polls prove to be correct, the victory will be particularly sweet for Mr Kejriwal, who was trounced by the PM when they both contested the constituency of Varanasi in May's general election.
In his extensive campaign, the Prime Minister described Mr Kejriwal as a "back-stabber" who fled office when things got tough.
Mr Kejriwal has everything to lose with this election. His disastrous decision to quit as Chief Minister in February was compounded by AAP collecting a scanty four seats in Parliament, emphasising that the party's only stronghold is Delhi.
Mr Kejriwal's campaign promised lower utility bills and free WiFi for Delhi's 1.7 crore residents, as well as pledges to counter corruption.