BEIJING  -- Beijing banned more than a quarter million high-emission vehicles from its roads on Tuesday, part of a drive to curb pollution ahead of the Olympics.

In the capital, about 300,000 high-emission motor vehicles that don't meet the exhaust standards won't be allowed on the road until September 20. However, their owners will be compensated with tax breaks and exemption from road maintenance fees during the period.

Previously, such vehicles were only allowed to hit the road in certain areas and hours.

Du Shaozhong, deputy director of the Beijing Environmental Protection Bureau, said the vehicles, about 10 percent of the total in Beijing, discharge about half of the total exhaust volume.

Vehicles registered outside Beijing must obtain special permits and meet emmission standards before entering the capital during the period.

At more than 110 checkpoints surrounding Beijing, traffic police and environmental protection staff began vehicle inspections on Tuesday. Cars, tractors and trucks that lacked the required permits were stopped and urged to leave the capital area.

The new emissions rules accompany other traffic restrictions, including alternate driving days for private cars starting on July 20 and taking half of the government cars off the road.

Despite worries over pollution and chronic traffic problems, Beijing environmental protection bureau statistics showed 13 more blue-sky days in the first six months than a year earlier, the best figure in nine years.