The Central Meteorological Observatory issued yellow warning signals from Wednesday to early morning Thursday for Shaanxi, Shanxi, Hebei, Heilongjiang, Jilin, Liaoning, Shandong, Henan, Jiangsu, Anhui and Hubei provinces.

Many areas will have low visibility, weather forecasters said, cautioning drivers on speed. Sandstorms will gradually move south and then weaken, forecasters added.

China has a four-tier, colour-coded weather-warning system, with red representing the most severe warning, followed by orange, yellow and blue.

Beijing, which was also issued a yellow sandstorm warning, has experienced sand and dust storms over the past several days, causing pollution levels to drastically increase.

Photos on social media showed people riding bicycles through the city amidst swirls of dust, with one showing a bike seat covered in sand.

Beijing on Wednesday recorded an air quality index of 500, pushing the pollution level to 6 - considered very hazardous to human health, according to the Beijing Ecological Environment Monitoring Center.

The city faces regular sandstorms during March and April because of its proximity to the massive Gobi desert, as well as deforestation throughout northern China.

(Reporting by Bernard Orr; Editing by Jamie Freed)