The errant driver, identified as Assistant Sub-Inspector Anil Kumar, has been arrested.
Eyewitnesses claimed that the driver of the bus was drunk, but his medical report was awaited.
The incident took place at around 3:30 P.M. When the bus, carrying around 20 policemen, was being driven towards Indira Gandhi Stadium for duty at a sports event.
"Kumar suddenly lost control and the bus hit the central verge and then jumped on to the opposite carriageway.
A case under Sections 279 and 338 was registered at Daryaganj police station. Further investigations are underway, police said.