The incident took place yesterday. The woman took a lift in the car occupied by three men from South Delhi. She was given cold drink laced with sedatives and after she fell unconscious the men allegedly raped her, police said.
Police sources said she was found near Nanakpura in a semi-nude and unconscious condition at around 7:30 am by a passerby, who informed police.
The woman, who resides in Kotla Mubarakpur, was taken to Safdarjung hospital, where a medical examination confirmed the sexual assault.
"She was unconscious. We recorded her statement later in the day when she regained consciousness," a senior police official said.
Some articles of the girl are also missing. A case under sections 376G (gangrape) and 378 (theft) of IPC has been registered.
A hunt is on to nab the culprits. Police believe that the woman hails from Nepal and she was thrown out of a moving vehicle near the Nanakpura footover bridge.