Authorities suspect that several government buses are operating in the city without mandatory fitness and pollution clearances.

One such bus crashed into a divider and toppled over on the Park Circus connector on Tuesday.

The vehicle’s driver, conductor, and four passengers are in hospital with multiple injuries.

A section of transport department officials admitted they had no clue about the number of buses that could be violating norms under their watch. They added that the department had “initiated a process” to identify such vehicles in the different depots.

The depot managers are responsible for ensuring that the vehicles are ready and fit for daily trips and have the mandatory certificates.

Tuesday’s incident was a blatant reminder of the inadequacies in the system. Multiple transport officials admitted that the depot manager neglected to carry out the checks before giving the bus the green light to operate.

The bus, which was travelling from Howrah to Kamagazi, did not have a valid fitness certificate. It lapsed in September 2017, almost nine years ago.

The vehicle did not have a valid pollution certificate. The validity of the certificate lapsed on July 31, 2024.

The bus was registered with the regional transport office in Howrah on October 1, 2015, almost a month after it was purchased. The vehicle’s registration was valid till September 30, 2017. The column on “ownership type” states: “Government Undertaking.”

The depot manager had not been formally hauled up till late on Wednesday.

Sources in the department said details about how the bus was allowed on the road were being “collected”.

At least 14 people were injured on Tuesday. Six of them are still in the hospital.

“Among several responsibilities of a depot manager, one is keeping tabs on vehicles that have to undergo fitness or pollution tests before they lapse. The fitness tests could have been performed in any of the regional transport offices. It was not done for almost nine years,” a senior transport department official said. “The vehicle is not even a decade old.”

Some officials in the department also came up with a defence. They were allegedly forced to roll out buses from their garages to meet the rise in demand during the Gangasagar Mela.

Hundreds of state-owned buses have been engaged at the annual event, which draws thousands of pilgrims from across the country.

“Ensuring their smooth commute is a challenge for the state government. Hence, buses from regular routes are withdrawn to meet the demand,” an official said.

Police said they have drawn up a case of rash and negligent driving against the driver and the conductor. But they are in critical condition at Calcutta National Medical College and Hospital.

“We will record their statements when they are ready to talk,” a police officer said.