BEIJING, Feb. 23 (Xinhua) -- China's national observatory renewed a yellow alert on Friday as fog lingered in east and central China.

Heavy fog will affect parts of the eastern provinces of Anhui, Jiangsu, Zhejiang and Jiangxi, the central provinces of Hubei and Hunan, as well as the southwestern province of Sichuan on Friday morning, according to the National Meteorological Center (NMC).

In some areas of Zhejiang, Jiangxi and Hunan, visibility will be reduced to below 200 meters.

From Friday night to Saturday, light to moderate rain will be seen in the southwestern and southern areas, and regions along the Yangzte River, according to the NMC.

China has a four-tier color-coded warning system for severe weather, with red being the most serious, followed by orange, yellow and blue.