Seven people were injured, five critically, when a speeding private bus caused a pile-up near Prinsep Ghat on Wednesday morning.

According to police, the bus hit two taxis that rammed into a Santro, which in turn felled a motorcyclist. “Four people in the taxis and the motorcyclist sustained serious injuries. They were taken to SSKM Hospital,” said an officer of the traffic control room.

The Howrah-bound bus hit the taxis around 11 am. One of the cars was smashed. “Such was the magnitude of the collisions that the motorcyclist was flung 30 metres from the spot,” added the officer.

The bus was impounded and the driver arrested. The vehicles involved in the pile-up were towed away to Hastings police station.

“The bus was travelling at a high speed. The driver lost control and hit the taxis. It could have been worse,” said a traffic sergeant, who witnessed the mishap.

In another accident, Aparna Pal and Asha Das were knocked down by a police bus on Rashbehari Avenue on Wednesday evening. Additional officer-in-charge of Kalighat police station Gautam Gupta said the bus, belonging to the fourth battalion of Calcutta Police, hit the two women while they were crossing the road.

They were taken to SSKM Hospital. Bystanders pelted stones at the bus. The driver was arrested.