"On behalf of myself and Delhi Police, I want to express my regret," Bassi told media.
He said the constable has been suspended.
"He has already been suspended," Bassi said.
The traffic constable, who has been identified as Satish Chandra, has been arrested.
He attacked the woman with a brick after an altercation.
Meanwhile, reacting on the incident, former Delhi top cop and BJP leader Kiran Bedi tweeted: "(This Cop be compulsory Retd) ..mother was stopped/for papers/bribe/abused/hit as she demanded receipt for fine. MT ."
Congress leader Sharmistha Mukherjee has condemned the incident.
Chandra, reportedly stopped the victim to check her driver's license and other papers .
The victim alleged that the constable had demanded Rs 200 as bribe from her.
She said the police hit her with a brick after she refused to pay the bribe.
"As I did not give bribe to him so he hit me with a brick," she told media.