The condition of Narsi Meena, posted at the office of Deputy Commissioner of Police (Traffic), is stated to be critical.
Meena was going to his office at around 11 AM when the accident took place as the car being driven by an advocate, Sanjeev Arora, hit him.
"Meena fell on the car's windshield resulting in serious head and leg injuries. He was crossing the road stretch between the former reserved bus lanes in BRT and the pavement outside the DCP (Traffic) office," police said.
Arora practises at the Delhi High Court. He was heading towards the Saket Court to meet a friend when the accident took place.
The constable was not in his uniform at the time of the accident.
Police have registered a case under relevant sections of IPC at Defence Colony police station, and also impounded the lawyer's car.