“I sent my resignation to Speaker Ram Niwas Goel on Thursday,” Singh, a former journalist, told IANS.
The Aam Aadmi Party has fielded Jarnail Singh from Lambi in Punjab to take on five-time Chief Minister Badal. Punjab goes to the polls on February 4.
Jarnail Singh has been actively campaigning for the AAP for many months. He was elected to the Delhi assembly in February 2015 from Rajouri Garden.