Thick fog continued to blanket parts of western and central China, forcing sections of expressways to close temporarily due to low visibility.

The fog will linger on Sunday in regions of north, east and west China, according to China Central Meteorological Observatory.

The meteorological observatory also warned of low visibility and delay of flights in these regions.

In central China's Henan Province, the provincial meteorological observatory issued red fog warning, the highest level, on Sunday.

Visibility in Zhengzhou, capital of Henan, reduced to less than 50 meters and motors vehicles have to move at snail's pace on the roads.

It is the 14th fog warning signal issued in Henan since October.

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

Meteorologists attributed the heavy fog to a combination of high humidity, lower temperature and low wind speed in the affected regions.

(Xinhua News Agency December 23, 2007)