Beijing authorities are likely to announce additional measures to curb pollution in the capital ahead of the Olympic Games, the China Daily reported on Monday.

The new measures would add to an already massive scheme to clear the city''s notorious smog, including the opening of three new subway lines, restrictions on car use, and temporary factory closures.

The state daily quoted Li Xin, a senior engineer working for the Beijing Environmental Protection Buearu, as saying: "We will implement an emergency plan 48 hours in advance if the air quality deteriorates during the August 8-24 Games."

The measures would include bringing even more vehicles off roads, suspending all construction, and shutting down more factories.

The environmental group Greenpeace said on Monday that despite major progress in energy and water-saving efforts, air pollution continues to be a threat to the health of athletes at the upcoming games.

However, Du Shaozhong, vice director of the Beijing Environmental Protection Bureau, disputed the claim, telling reporters: "We can ensure clean air during the Olympics, and are sure that air quality in Beijing will not harm the health of athletes."

He said that the smog, which persisted on Monday, was due to a combination of emissions and bad weather.

Vehicles are a major cause of pollution in Beijing, with around 1,000 new cars hitting the capital''s roads each day until the restrictions kicked in. Under the current scheme, cars with even and odd number plates are permitted on the roads on alternate days.

The China Daily quoted environmentalist Zhu Tong as saying the city needs a 90% vehicle cut for the games. Zhu proposed that only vehicles whose license plates end with the last digit of the date for any given day should be allowed on the capital''s roads.

As part of pollution reduction measures, Beijing has increased its bus fleet to cut car use, and suspended operations of cement and petrochemical plants until September.