India bus crash: Twenty nine killed after bus plunges off motorway bridge

At least 29 people have been killed after a bus smashed through a motorway bridge and plunged off the road in northern India.

Most passengers were sleeping when the bus fell into a 30ft-deep drain near Agra in Uttar Pradesh, according to a government spokesman.

The bus was on its way to New Delhi from Lucknow, the state capital on the Yamuna Expressway - one of India's busiest roads.

Spokesman Awanish Awasthi said 18 injured passengers were also taken to hospital, with six of them in a serious condition.

One official speculated that the driver had 'dozed off'.

Onlookers and Indian police gather around the crumpled remains of a bus that crashed on the Delhi-Agra expressway. (AFP/Getty Images)

Reports say at least one child has died in the accident.

The cause of the crash is being investigated, he said.

Emergency workers alongside the damaged remains of a bus after it fell into a deep drain on Yamuna Expressway. (EPA)

"The bus was speeding and the driver probably dozed off," said District Magistrate N. G. Ravi Kumar.

Emergency workers alongside the damaged remains of a bus after it fell into a deep drain on Yamuna Expressway. (EPA)

Mr Kumar did not know whether the driver was among the dead.

India has the world's deadliest roads, with about 150,000 killed and 470,000 injured annually.

Most crashes are blamed on reckless driving, poorly maintained roads and ageing vehicles.

Agencies contributed to this report.