The incident took place yesterday night under the Civil Lines police station here when the police noticed unidentified accused fleeing in a mini-truck after looting cattle, SP (City) Om Prakash said.
The policemen, including an Sub-Inspector, started chasing the suspects in their van and later both the vehicles landed into collision.
The injured Sub-Inspector was identified as Pinki along with the other police constables - Rahul, Atul and Ramesh. They were rushed to the hospital but later discharged after treatment, he added.