Barely two weeks after this winter's first heavy fog hit most parts of China on December 2, many people's travel plans were stymied again on Tuesday as another loomed over several cities.

Dense fog has affected Shanghai since Saturday. At 7:06 AM on Monday, the local meteorological station forecast visibility would drop below 50 meters in some suburban areas including Baoshan, Minhang and Jiading.

At least 40 flights were delayed on Monday at Hongqiao Airport, though flights in and out of Pudong Airport were not affected. Major expressways linking Shanghai to other provinces were closed as well.

The fog also affected water transportation in Shanghai. Four water passages in the Songjiang and Minhang districts were closed from 5:30 to 7:10 AM on Monday.

In Chengdu, capital of Sichuan Province, heavy fog delayed more than 30 flights and laid over several thousand passengers at Shuangliu Airport, where visibility was less than 100 meters at 3:00 AM.

Sources with the city's meteorological station said the airport was the worst affected region in the thick fog that was shrouding most parts of Chengdu.

The local road transport authorities closed all major expressways early in the morning, including the expressways linking Chengdu with neighboring Chongqing Municipality, and the cities of Ya'an, Mianyang and Nanchong.

Beijing temporarily closed its suburban sixth ring road early on Tuesday as visibility dropped below one kilometer. Two expressways linking the capital with neighboring Tianjin Municipality and Hebei Province were also partially closed.

Officials from Beijing's Transportation Bureau said road traffic in the city proper was largely unaffected, though more people were opting to travel by bus or subway instead of driving their own cars.

The public bus company and subway operator were ready to provide more buses and trains when passenger numbers increase during rush hour, sources with the bureau told Xinhua News Agency.

There were no reports of flight cancellations or delays at the capital's airport, and railway authorities say all incoming and outgoing trains are on time at the two major railway stations. But meteorological experts predict the foggy weather will linger a day or two, until a cold current dispels it on Thursday or Friday.

The daily report on air quality in 47 major cities released by the China Environmental Monitoring Station on Monday said that particulates in the air of 19 cities have increased drastically in the past three days.

As dense pollutants in the air can affect the respiratory system, health experts have advised the elderly, children and people with respiratory diseases to avoid outdoor exercise and to wear masks.

(Xinhua News Agency December 15, 2004)