Children are often crammed into buses for their journeys to school in China, especially in rural areas.

Two children on an overcrowded van being used to take them to school were injured when it was rear-ended by a public bus in Shanghai yesterday.

The van had been hired by parents, police said. Eleven children were onboard the vehicle but it was only licensed to carry seven passengers.

The accident happened at about 6:50am.

Two sisters, surnamed Liu, were sitting in the rear seats of the van when it was hit by the bus. The elementary school pupils weren't seriously hurt but needed hospital treatment.

Shanghai police said yesterday that they regularly conducted safety checks on school buses in the city.

Buses used by major schools had not been found to have problems such as overloading, speeding or unlicensed drivers but officers acknowledged that wasn't always in the case in some suburban areas, such as yesterday's case in Songjiang District.

"Some parents claim they used car/bus-pooling to send their children school," said a traffic police official surnamed Yu.

"That make it hard for us to define whether it's legal or not."

The Shanghai Education Commission issued a notice yesterday ordering district education bureaus to launch an immediate inspection of all school buses to be completed by next Friday.

Shanghai has about 2,200 school buses which carry some 60,000 students to kindergartens and primary and secondary schools every day.

The checks ordered by the commission will cover drivers' licenses, safety equipment such as hammers and fire extinguishers, and the overall state of the vehicles, officials said.

Meanwhile, the commission has asked schools to impress upon parents the importance of school bus safety and to stop parents from chartering illegal vehicles for the school run.

Shangai's school bus regulations stipulate that school buses need special licenses from the education authorities before being allowed on the road.

School bus drivers must have at least three years' experience and good records.

The regulations also state that all students should have their own seats and use seat belts. Standing on board buses is not allowed.

School buses must also carry special logos and be painted yellow so that other drivers are aware that there are children on board the vehicles.

"Ensuring the safety of school buses is an important task for us," said Yang Yongming, a commission official in charge of youth safety.

Shanghai education authorities have been carrying out monthly spot checks on school buses.

In a recent inspection on five schools in Xuhui District, seven buses out of a total of 16 were found to have problems with their lights and two had defective fire extinguishers, education authorities said.