BEIJING - China is stepping up joint efforts to remove high-emission vehicles from roads.

Enterprises are required to replace all high-emission commercial vehicles registered before the end of 2005 this year, a target set in March in an effort to improve air quality, according to a joint notice released by the Ministry of Environmental Protection, the Ministry of Public Security, the Ministry of Finance, the Ministry of Transport and the Ministry of Commerce on Wednesday.

Vehicles that meet the country's standards for mandatory scrapping but are illegally still on the road will be removed through more thorough checks and their registration certificates and license plates will be declared invalid by the police.

Chinese authorities also called on tougher supervision for the procedure of disposing of old vehicles and used car markets nationwide, preventing dealers selling dismantled spare parts of written-off vehicles to consumers.

Incentive policies will be adopted to remove high-emission vehicles from roads. For instance, local authorities are considering raising subsidies for scrapping high-emission taxis, buses and heavy cargo trucks.

According to statistics released by the Ministry of Environmental Protection, as of the end of September, China removed 823,600 high-emission vehicles nationwide, accounting for 70 percent of total targeted vehicles.