A jam along China's Beijing-Tibet highway has grown to more than 75-miles long as the tail back of cars extended into its third day.

The jam started near the Chinese capital on Tuesday, as traffic restrictions in Hebei province caused tailbacks along the highway.

Traffic build-ups have become a common occurrence on the country's roads - just over one week ago the authorities finally managed to clear a 62-mile jam from the same road which had lasted for nine days.

Most of the 10,000 vehicles in the hold up are coal lorries and they are also blocking feeder roads leading onto the highway.

China is the world's top producer and user of coal, which has fuelled its rapid economic growth over the past three decades, and the area has large reserves.

While China is spending billions of dollars on infrastructure such as roads and railways, it is still struggling to keep up with the demands of its booming economy.