Thick fog continued to blanket parts of western and central China Sunday, causing traffic accidents, flight delays and highway closures.

Plunging visibility from the bad weather delayed more than 150 flights and left 12,000 passengers stranded Sunday in the Shuangliu International Airport in the capital of Sichuan Province, airport officials said.

The airport was closed for nearly nine hours Sunday morning before a flight to Tibet took place at 11:10 AM.

"Full operations did not return to normal until more than an hour later when the first flight from Shenzhen in Guangdong Province landed here," airport publicity department official Liu Gang told China Daily.

"It was the second day visibility in the airport had been at about 10 meters."

On Saturday morning, a heavy fog fell on Chengdu, shrouding its downtown areas and six suburban counties with a visibility of under 50 meters.

The airport itself was closed for eight hours that day, with 121 flights delayed and 11,000 passengers stranded.

Sichuan weather bureau deputy chief Zhong Xiaoping said environmental pollution was a major cause of the fog.

Zhong advised citizens to take buses more often, save energy, cut car exhaust, and play a part in the recycling of waste materials.

More than 10,000 vehicles were stranded from the fog on highways Sunday, about 4,000 more than the day before, the Chengdu Transportation Bureau said. It advised residents to take trains in the next few days.

He Ping, a 49-year-old company employee, drove from Deyang in northern Sichuan to Chengdu through the Chengdu-Mianyang Expressway Sunday afternoon.

"I've driven for nearly 20 years and have never seen such heavy fog before. I could not even see the line separating the fast lane from the slow one," He told China Daily.

Meanwhile, heavy fog also persisted in Hebei, Henan and Shaanxi provinces for consecutive days. The poor visibility forced highways to close and delayed flights Sunday.

The Xi'an-Baoji Expressway in Shaanxi Province was closed on Saturday as visibility in some sections was less than 2 meters.

Meteorologists also attributed the fog to a combination of high humidity, lower temperatures and low wind speeds in the affected regions.

(Xinhua News Agency December 24, 2007)