Clamping down to clean up the air

When a red alert, the highest-level warning, is issued for smog in northern China, vehicle traffic is cut by half, factories are ordered to suspend production and schools close. Zheng Jinran and Zhang Yu visited Baoding, a city in Hebei province, whose 11 million-plus residents have been living under a month-long red alert for smog.

On Christmas Eve, Liu Hao bought a larger-than-usual amount of stock for his roadside store, not because business is booming as New Year approaches, but as a result of license plate restrictions on the use of vehicles that mean he is only able to visit the warehouse on alternate weekdays.

For the past month, Liu has only been allowed to use his small van two or three days per week, one of a series of measures imposed by the government of Baoding, Hebei province.