The emergency door at the back of the vehicle through which the injured were rescued Bishwarup Dutta

The police said the bus, hired by guardians, was on its way to the north Calcutta school when it met with the accident at the Cossipore Road-PK Mukherjee Road crossing.

“The driver said the brakes had failed. But the findings of a preliminary probe suggest there were no problems with the brakes. The accident was possibly caused by rash driving,” an officer said.

The bus, after picking students from Baranagar, Belghoria and Dunlop, had taken the Lockgate flyover and was trying to take a left turn towards Tallah when it apparently went out of control.

“The bus was moving at high speed. Suddenly, the bus tilted and we all fell on one side. Then everything blacked out. When I came to I found myself being taken out by some uncles,” recounted a student.

“My cousin Tirtha Ganguly was accompanying his daughter Tayasmita to school on the bus. Tayasmita suffered injuries on her cheek bone and my cousin on his head. We shifted both to another hospital for better treatment,” said Bimal Chakraborty. Tayasmita, 14, is a Class IX student.

Srishti Chaudhury, 13, a student of Class VIII, suffered shoulder injuries. “She was in severe pain. Initially, we thought she had fractured her shoulder. But the X-ray report was not that bad,” said Sukanta Chaudhury, a relative.

An officer said one of the students bled so much that she had to change into a new set of clothes before stepping out of the hospital.

People in the neighbourhood were the first to rush to rescue. A team from Chitpur police station, too, arrived at the spot soon after the accident.

Sister Roshni Monteiro, the principal of the north Calcutta school, went to RG Kar hospital after hearing about the accident. “Eight children suffered injuries on hands, shoulders, head and face.... I tried to console the children, who were traumatised because of the accident,” Monteiro told Metro later in the afternoon.

Class VII students had their computer practical exams on Monday. The school said those who failed to appear in the exam because of the accident would be allowed to write their papers at the end of the theory exams.

A case of rash and negligent driving, causing grievous hurt and endangering other’s life has been started against driver, Sonul Haldar, 24.

Eight pupils were injured when a bus that regularly ferries students to school toppled on its side after smashing into a signal post and running into a mound of sand near the base of the Chitpore

Lockgate flyover in Bagbazar on Monday.

The bus was carrying 12 students of Holy Child Institute, on Abhedananda Road (Beadon Street), and six guardians.

“The injured students were aged between 11 and 15. They suffered face, hand and head injuries,” a police officer said.

The six guardians were also injured. One of them fractured her hand. Dhananjay Bhunia, 30, a cyclist whom the bus had hit before it rammed into the signal post, was injured in the spine.

The injured were all taken to RG Kar Medical College and Hospital.

Four students — the youngest of them was aged five — escaped unhurt.