The strongest sandstorm in almost two decades hit Gansu province in northwest China on Wednesday.
Beginning in Dunhuang county in the early afternoon, the storm reduced visibility in the region 20m (65ft), according to the Jiuquan City Meteorological Centre.
Schools in the area warned parents to keep their children at home, the South China Morning Post reported.
The centre issued a red alert – the highest possible – and forecast that visibility would be reduced to less than 164ft throughout Jiuquan on Wednesday evening.
The neighbouring counties of Guazhou, Subei, Yumen and Jinta counties also issued sandstorm red alerts.
“Suddenly it became dark and I can't tell whether it's day or night,” said one resident.
“My nose hurts and I can't open my eyes,” another resident said.
As Dunhuang is situated near the Gobi Desert, which stretches across Inner Mongolia and northern China, the area is prone to enormous sandstorms in springtime which can reach the capital, Beijing, the newspaper reported.
The centre predicts the storm will subside by Thursday.
Additional reporting by Reuters