China's national observatory Wednesday renewed a yellow alert for thick fog that will affect most parts of the country.
From Wednesday morning, thick fog will sweep parts of Jiangsu, Anhui, Hubei and Liaoning, according to the National Meteorological Center.
The visibility in parts of the areas will be reduced to less than 50 meters, the center said.
It suggests drivers in affected regions slow down, while airports, expressways and ports take appropriate safety measures.
China has a three-tier color-coded warning system for fog, with red being the most serious, followed by orange and yellow.