Beijing's overall air quality improved during the four-day test period carried out in anticipation of next August's Olympic Games. More than a million cars each day were barred from the roads, according to the Beijing Environment Protection Monitoring Center.

The test resulted in the removal of five million cars from downtown Beijing roads. Beijing's air quality was classified as "fairly good" for the duration of the four days.

"The index of inhalable particular matter (IPM), a major air pollutant, was 91, 93, 95, 95 over the past four days, as compared to 116 on Thursday," said Zhao Yue, a senior engineer affiliated with the center.

"The wind speed has been low in recent days, which was not conducive to dispersing the pollutants in the air," he added.

An unhealthy haze still hung over the city throughout the weekend. Zhao commented, "The vehicle ban has definitely improved the city's air quality."

A reduction in traffic congestion was the most obvious benefit of the program.

Monday's traffic on almost all roads in downtown Beijing was even better than the first three days, reported Shao Jie, an official with the transportation department of the Beijing Public Security Bureau.

"I have never seen smooth-flowing traffic during rush hour on a Monday like this before," Shao said.

Statistics from the municipal transport authorities showed that the jammed road sections only accounted for 0.1 percent of the total roads on Monday, whereas on the previous four Mondays, the figure stood at 5.8 percent.

(Xinhua News Agency August 21, 2007)