AAP candidate Ram Chander is 20,000 votes ahead of his nearest Congress rival Surender Kumar after the 21st round of counting of votes for the Bawana bypoll.
So far, Chander has polled 47,554 votes and Kumar has bagged 27,090. The BJP's Ved Prakash is at the third place with 26,406 votes, the Delhi CEO office said.
AAP workers, who gathered outside the counting venue at Alipur broke, into celebrations as the signs of Chander's victory became brighter with his growing lead.
The AAP candidate, who trailed behind Kumar and Prakash till the sixth round of counting, surged ahead at the end of the 14th round.
His lead widened to over 15,000 votes by the end of the 18th round.
The counting, which began at 8 am, is likely to go on till 28 rounds, officials said.
Bawana is one of the largest constituencies in Delhi in terms of number of voters (2.94 lakh).
The by-poll, which was held on August 23, saw a meagre turnout of 45 per cent. A total of eight candidates are in the fray.
The Congress is hoping for a victory in the bypoll to open its account in the Delhi Assembly. The party had drawn a blank in the 2015 Assembly elections.
In the 70-member Delhi Assembly, the AAP has 65 MLAs and the BJP 4.
(This story has not been edited by Business Standard staff and is auto-generated from a syndicated feed.)