Test ban

Beijing tested its vehicle-control policies for the Olympics from August 17 to 20, 2007, when private cars with even-numbered and odd-numbered licence plates were told to stay off the roads on alternate dates or be fined. According to the Beijing Environment Protection Bureau, tests showed air quality improved. NOx and CO emissions and particulate matter were cut by 87, 1,362 and 4.8 tonnes on four days of testing. The amount of pollutants fell by 5,815.2 tonnes, a 15-20 per cent cut.