NEW DELHI, Sept. 23 (Xinhua) -- More than 50 people have been injured after a bus overturned and fell into a ditch in the northern Indian state of Uttar Pradesh, police said Sunday.

The accident occurred at Haredi bypass on the Delhi-Haridwar national highway in the state's Muzzaffarnagar district.

"The bus carrying some 60 passengers overturned after its driver failed to spot a pothole on the road. Some 50 people sustained injuries in the accident," a police official said.

Eye-witnesses told cops that the bus was travelling at a speed above the permissible limit as a result of which the driver failed to apply brakes when the vehicle fell into the pothole.

A probe has been ordered into the incident, the official said. "The driver of the bus could be booked for rash and negligent driving after the probe," he added.

India has the highest number of road fatalities in the world. Road accidents occur mostly due to poor driving or badly maintained roads and vehicles.