BEIJING - China's meteorological authority issued a yellow alert for foggy weather as heavy fog will continue to shroud central and eastern China on Friday.

Heavy fog will persist this morning in Anhui, Jiangsu, Shanghai, Zhejiang, and parts of Shandong, Hebei, Henan, Hubei, Fujian, Jiangxi, Hunan, Sichuan, Chongqing, Guizhou, Guangxi and Guangdong due to inactive cold air and possible smog created by firecrackers as Chinese celebrated the lunar new year, with visibility in some regions reduced to less than 200 meters.

The NMC advised people in the middle regions along the Yellow River and Huaihe River and the mid and lower reaches of Yangtze River to reduce setting off fireworks.

China's meteorological alerts are categorized as blue, yellow, orange and red as the severity ascends.

Central China's Zhengzhou city is shrouded in dense fog, Jan 31, 2014. [Photo/Xinhua]