[Photo by LIU CHEN/CHINA DAILY]

According to Pan Tao, deputy head of Beijing Research Institute of Environmental Protection, the restrictions on the use of vehicles played a bigger role than industry in reducing major air pollutants.

Additionally, to reduce air pollution for the parade, Beijing and its six neighbors, including Tianjin and Hebei province, imposed pollution controls during the period.

Some 70 counties and cities in the region saw an average 40 percent reduction of PM2.5, Pan said. Without the effective controls, Beijing's PM2.5 would have been 70 percent higher, or a rise of 17.8 micrograms per cubic meter, Pan said.

"We have imposed stricter restrictions to curb air pollution, and conducted more frequent inspections to make the implementation better," said Fang Li, the deputy head of the bureau.

Pan and Fang agreed that the measures to curb air pollution were more effective than those adopted for the Asia-Pacific Economic Meetings in November. The regional average decrease of PM2.5 during APEC was around 38 percent－lower than the average decrease, Pan said.

Around 2,000 companies suspended production this time, 15 times the scale of the APEC period. Beijing authorities inspected more than 46,000 companies, 13,000 construction sites and 690,000 vehicles during the period.

"We have exposed over 1,000 violations, mainly from vehicles with excessive exhaust emissions and outdoor barbecues," said Liang Wenyue, deputy head of the atmospheric management department of the bureau.