Voting is underway at the Rajouri Garden constituency to choose its new MLA in the sole by-election in the national capital on Sunday.
According to the election office, voting began at 8 am and will continue till 6 pm in the area which has around 1.6 lakh electors.
The seat fell vacant early this year after the Aam Aadmi Party's (AAP's) Jarnail Singh quit as MLA to contest the Punjab Assembly poll against the Shiromani Akali Dal (SAD) patron Parkash Singh Badal.
Along with electronic voting machines, the reliability of which has been questioned by the AAP, voter-verifiable paper audit trail are being used at all the 166 polling stations of the west Delhi constituency.
For the Bharatiya Janata Party (BJP) and the Congress success in the bye-election is crucial for their continuing relevance in the city's politics while it will be a test for the AAP's popularity.
The AAP has come up with a new face - Harjeet Singh - for the election while the Congress has fielded Meenakshi Chandela, who belongs to a politically influential family of the area.
The BJP-SAD combine has fielded veteran Manjinder Singh Sirsa who had won the seat in 2013.