Heavy fog hit Beijing on Saturday morning, resulting in traffic chaos, and warnings for children and the elderly not to go outside.

Dense-fog alarms were sounded at around 5:20 AM and 11:00 AM on Saturday. Visibility in the city was down to 200 meters.

Seven of the city's expressways were closed between 5:05 PM on Friday and 3:00 AM the following morning.

Beijing was not the only area affected, as fog covered almost the entire eastern part of the country on Saturday.

Yang Guiming, from the National Meteorological Center, said it was the country's heaviest fog this autumn, with northeast China, north China and south China all affected.

Tianjin and Hebei Province were the worst-hit area with visibility down to just 100 meters.

Between Thursday and Saturday, air pollution in Beijing reached category five, a standard reserved for only the most seriously polluted air, according to the local environmental protection bureau.

Experts said huge daily emissions and unfavorable weather conditions were the main culprits for the worst air pollution Beijingers have experienced so far this autumn.

Yang said low pressure and fog, which arrived last Tuesday, have prevented air from circulating, with pollution rapidly accumulating in the stale atmosphere.

The heavy fog is harmful to health, Yang said, suggesting people, especially the elderly and children, should reduce outdoor activities to avoid inhaling too many pollutants.

Yang also suggested people keep their rooms ventilated, drink more water and eat plenty of fruit and vegetables to stay healthy.

(China Daily November 7, 2005)