Beijing has been soaked in dense fog since Tuesday afternoon and a greater part of China was shrouded in mist Wednesday.
The visibility in the city was less than one kilometer Wednesday morning and five of the eight expressways were closed temporarily due to the heaviest fog this winter.
The heavy fog is looming over most of northern China, southwestern China, northeast China's Liaoning Province and the lower reaches of the Yangtze River, according to the Central Meteorological Station (CMS) Wednesday.
In some areas of north, central and east China, the visibility is only 100 to 200 meters with the air quality rapidly deteriorating, said Yang Keming, senior engineer of the CMS.
A mass of fog with an area of approximately 217,000 sq km covered up Beijing and Tianjin municipalities, parts of east China's Shandong Province and north China's Hebei Province Tuesday evening, which was monitored by the weather satellite, Yang said.
He went on to explain that the unusual heavy fog resulted from a humid and warm air currents from the Qinghai-Tibet Plateau in the past few days, relatively cold weather and gentle wind over these regions.
The foggy weather will continue until Saturday when a cold front is expected to arrive causing snow, rain and strong winds blowing off the fog, Yang added.
The possible four days of misty weather have made Beijing harder still to realize its goal of having 18 days of clear blue sky with good air quality this month.