BEIJING, Nov. 7 -- Beijing and several provinces in the north and east of the country were blanketed in dense fog Saturday, causing traffic accidents and delays, and forcing authorities to close seven expressways from Beijing to Shenyang, Shijiazhuang and Tianjin.

　　For the thi rd consecutive day, air quality in the capital was categorized at level five, or hazardous. The visibility was only 200 meters.

　　The meteorological center of Beijing issued heavy fog warnings and seven motorways were closed twice by traffic police.

　　Beijing, Tianjin and parts of 10 other provinces were covered by thick fog. Some northern and eastern provinces including Hebei, Shandong, and Anhui were particularly hard hit, with visibility between 300 and 800 meters, CCTV reported.

　　The Beijing News said the air pollution was the worst in the past six months as suspended particle count reached a dangerous 300 micrograms per cubic meter.

　　According to the meteorologists, a gale of cold air blew southward to Beijing on Saturday afternoon but failed to disperse the fog immediately.

　　Low visibility caused four trucks to collide on a Beijing ring road, killing at least three people and injuring eight others. The expressway from Beijing to Shenyang was closed Friday afternoon due to low visibility and a nine-car pileup Saturday at Beijing-Tianjin-Tanggu Expressway killed three and injured seven.

　　The visibility in Beijing airport was 1,000 meters. Though flights were not affected, the flight control department of the airport expanded the flight departure intervals for safety reasons and restricted the number of flights. Some flights were delayed for half an hour for the heavy fog.

　　(Source: Shenzhen Daily)