"Concerns (over pollution) within the IOC executive board were eased," IOC director of communications Giselle Davies told reporters on Monday after receiving a progress report from Beijing organisers earlier in the day.

"They have a plan from Aug. 7-20 this year: one million cars will be off the road."

She said organisers would trial several plans this year that are designed to prepare the city for the Olympics.

"Obviously the test events provide an excellent opportunity to try out contingency measures that may be used if necessary at the Games," said Davies, who is in Guatemala City for Wednesday's announcement of the host venue for the 2014 Winter Olympics.

Organisers have also said Beijing authorities would replace about 50,000 old taxis and 10,000 buses by the end of the year as well as renovate 16,000 coal-burning factories.

China has slowed, but not reversed, a rising tide of pollution from frenetic industrialisation, the national environment agency said last month in the face of increasing public anger over foul air and water.