“We usually follow the state policies on pollutant discharge fees,” said Du. “Beijing had suggested tightening the management on vehicle tail gas after the Beijing Olympics. But relevant state departments are still doing research on the policy.”

He said the city has made many efforts to reduce the air pollution caused by vehicles. Among a series of actions, 576 yellow-tagged cars, which refer to vehicles with a higher volume of pollutant discharge than the state standard for urban area, were removed from Beijing before the Spring Festival.