cars were off Beijing's streets from August 17-20. The city officials decided to experiment in a drive to check pollution and ease the city's traffic. Traffic congestion and brown haze have been perpetual causes of anxiety for officials, ever since Beijing won the Olympics bid in 2001. The president of the International Olympics Committee said the rising pollution levels could prevent certain events from being held in the Olympics scheduled for next year.

The experiment involved banning cars from the capital's roads following an odd-even number plate system. As a part of the plan, all private vehicles with licence plates ending in even numbers were pulled off the roads on August 17 and August 19. Odd-number licence vehicles were pulled off on August 18 and August 20. The idea was to keep 1.3 million cars off the roads, nearly more than a third of the city's car population. Beijing is home to three million cars and adds 1,000 cars a day.

Despite the experiment, the city continued to be cloaked in grey haze. Beijing's environment protection bureau claimed that the city had an air pollution index of 95-93 during the test days amidst unfavourable weather conditions that stalled dispersal of pollutants. According to the official agency an air quality index rating below 100 indicates good conditions. The index rolled back to 116 the day normal traffic resumed.