Four policemen were injured when a police Gypsy in which they were travelling collided with a city bus coming from the opposite direction near the Forest Research Institute on Monday. These policemen were deputed for escorting inmates from Suddhowala jail to court and back. The accident took place at around 4 pm when these policemen were returning from Suddhowala jail. The injured policemen are head constable Chandilala, constables Pavan, Pushkar and Amit Saini. They were admitted in a local hospital. In this mishap, Pavan was seriously injured, it is learnt.