"People were warned to stay indoors Friday as thick smog blanketed Beijing for a third day, with hospitals reporting increasing numbers of people seeking treatment for respiratory problems. The grim weather was also causing transport chaos with flights delayed and accidents reported on the roads. Officials urged people not to drive to avoid worsening the pollution, Xinhua news agency said.
Caused by humid and warm air currents blown down from the Qinghai-Tibet Plateau, the mass of smog was hanging over much of north, northeast and southern and southwestern parts of China, state media said. In the Chinese capital, visibility was down to less than 100 metresfeet) with some areas reporting just 10 metres (33 feet). The Beijing Environmental Protection Agency issued an alert on its website warning citizens that the smog could result in health issues and urged people to limit their time outdoors.
Hospitals across the city reported a rise in people seeking help for respiratory problems, the Beijing Times said. "Respiratory disease and infection especially in the elderly and children are caused by the high level of fog, humidity and cold air and because of the high amount of suspended particles," a doctor surnamed Lin from the Haidian Hospital said. "In the last couple of days in our hospital the numbers of people infected with respiratory diseases has clearly gone up."
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http://www.terradaily.com/2004/041203033602.0i4b2ai0.html