Balli said that he had made a "mistake".
"I repent my decision of leaving the BJP and joining the Congress. My return to the party is a remorse for the mistakes that I have committed.
"I would work for the welfare of the party without any conditions," said Balli.
In joining of Balli, the Delhi unit of BJP found a prominent Sikh face in its fold. Balli had quit BJP after he was denied ticket to contest 2013 Delhi polls.