BEIJING - Beijing will implement a spate of temporary measures that include stopping construction and closing heavy-polluting plants to ensure clean air for this August's Olympic Games, a municipal environmental official said on Monday.

Du Shaozhong, deputy director of Beijing's Environmental Protection Bureau, told a press conference that all digging and pouring of concrete on construction sites will be suspended from July 20 to September 20, and nineteen heavy-polluting factories have also been ordered to reduce their emissions in the same period by a further 30 percent.

Even more strident measures could be taken "in case of extremely negative meteorological conditions", he added.

Along with cleaning up Beijing, China's central government has also given nearby provinces and municipalities targets to reduce pollution by using air-cleaning technology and closing some industry.

Beijing, which is sometimes shrouded in smog, has spent more than US$ 15 billion over the last decade to clean its air and the improvement is obvious.

The city notched up 67 "blue sky days" from January to the end of March, 12 more than the same period a year earlier and the highest in nine years, according to Du.

IOC president Jacques Rogge said earlier this month that the city's pollution will not endanger the athletes' health.