BEIJING  Faced with persistent air pollution despite promises to stage a green Olympics, Beijing is planning to reduce its motor traffic by half during the Games to improve air quality and ease traffic flow, according to a newspaper report on Wednesday.

The article, in The Beijing News, said the number of vehicles in the city was expected to reach 3.3 million by August, meaning that roughly 1.65 million cars and trucks would be pulled off roads each day. The city will dedicate lanes to Olympic traffic and increase public transportation with new shuttle buses to accommodate visitors and local residents, the article said.

Beijing officials have not announced Olympic contingency measures, but the newspaper said the traffic plan had been completed.

The city’s air pollution  ranked by some studies as among the worst in the world  is one of the most pressing challenges facing Olympic organizers, with fewer than 200 days until the opening ceremony on Aug. 8. Many Olympic teams plan to train outside the city to protect athletes. Besides whatever measures Beijing officials take to reduce pollution, factories throughout north China may face shutdowns during the Games.