Kolkata: At least 30 persons were injured after a bus toppled into a roadside waterbody on its way to Digha early on Monday morning. Local residents and police rescued the injured passengers and rushed them to Contai Sub-Divisional Hospital.According to sources, on Monday morning a bus full of passengers was running along the Contai-Nandakumar Road at a high speed, on its way to Digha. At around 4:30 am, the driver lost control over the bus near Marishda and it toppled into a roadside waterbody. Locals heard the sound of the accident and screams by the passengers and ran towards the bus. The driver and the helper had somehow managed to jump out of the bus before it fell into the waterbody. Several passengers got stuck inside the bus, while a few others were in the water. Local residents started a rescue operation and informed Marishda police station. Within a few minutes, police arrived at the spot and rescued the passengers with help from the locals. All the injured persons were rushed to Contai Sub-Divisional Hospital, where they are still undergoing treatment. Sources informed that a few of the injured are in critical condition. Police are trying to contact the families of the injured persons. It is suspected that while driving the driver must have fallen asleep, due to which he lost control over the steering. Police will check the bus to ascertain if any technical fault was there. According to locals, the bus had met with the accident due to excessive speed. A probe has been launched in this regard. Search for the driver and helper is on.