The driver of the bus that fell into the canal will be charged with culpable homicide not amounting to murder.

It is a non-bailable offence, unlike the charge of causing death by negligence, generally slapped on drivers involved in fatal accidents.

The driver, as well as the conductors and the owner of the bus, had not been identified till late on Friday.

“We have decided to charge the driver under Section 304 of the IPC to teach him a lesson. There’s an intersection and a curve on the road near the accident spot. The driver should have been cautious but he did not even follow the basic principles of driving,” said deputy inspector-general (Presidency range) Soumen Mitra.

“We have found out that from Kankurgachhi, the conductor on the front gate had been urging the driver to go faster. Even at the accident site, the driver was trying to overtake an autorickshaw. He should be taught a lesson. We will punch his licence,” said district police superintendent Supratim Sarkar.

If proven guilty under Section 304 of the IPC, the driver could be jailed for up to 10 years. Senior lawyers, however, said it would be difficult to put him behind bars. “It is almost impossible to prove that the driver wanted to kill the passengers and was, therefore, speeding dangerously. Besides, it is difficult to prove that the bus was speeding when it skidded,” said a lawyer.

The bus will be sent for a mechanical test, said the police. If any mechanical glitch is detected, proving that the driver was guilty as charged will become even more difficult.

“The case can drag on for years, as it generally happens. The witnesses sometimes fail to turn up, resulting in the driver being acquitted,” said an officer. According to the police records, the rate of conviction in cases of fatal accidents is very low.

The state and the city traffic police have sent a proposal to the Centre, through the home secretary, seeking more stringent punishment for driving offences.