But cars registered before that time will not be forced to meet the standard.

Beijing started to implement Euro I emission standards in January 1999. The standards are based on the regulations for new heavy-duty diesel engines that were first introduced in 1992 by the European Parliament and the Council of Environment Ministers.

Beijing's decision to implement Euro II standards comes in the wake of public appeals for clean air and the soaring number of vehicles.

The latest statistics indicate that the number of cars in the city has reached 1.7 million. The number is increasing fast and is predicted to reach 3 million by 2008.

Vehicle emissions are one of the major sources of pollution in the capital's atmosphere.

About 60 percent of the city's nitrogen dioxide in air and 70 percent of hydrocarbons come from automobile emissions, according to environmental experts.

Tougher standards help limit emissions of harmful gases such as carbon monoxide, hydrocarbons and nitrogen oxide.

Euro II standards demand a 60 percent reduction of such harmful emissions on average compared with Euro I standards.

For instance, Euro II standards stipulate that hydrocarbon discharges should not exceed 0.5 grams per kilometer for a petrol-powered vehicle, 0.63 grams lower than Euro I standards.

Carbon monoxide emissions should not exceed 2.2 grams per kilometer under Euro II standards. This is 0.96 grams lower than what Euro I standards demand.

Most new vehicles have reached or exceeded Euro II standards, according to the bureau.

Beijing authorities hope to improve the environment for the 2008 Summer Olympics and the city is looking at the introduction of Euro III standards by 2005.

(China Daily June 17, 2002)