The woman told police that she was waiting for a bus when a car stopped near her and two men dragged her in. She said that two more men joined them later and all four raped her in the moving car.
She said that she was thrown out of the car after being attacked.
Additional Deputy Commissioner of Police Harjit Singh Brar said the "victim was admitted to a government hospital here and was examined by doctors".
He said police were trying to identify the accused and check whether they were known to the victim.