BEIJING, April 5 (Xinhua) -- China's meteorological authorities issued a blue alert for sandstorms on Thursday, forecasting wind and dust for the country's northwest regions.

From Thursday to Friday morning, parts of Xinjiang, Qinghai, Gansu,Inner Mongolia, Ningxia, Shaanxi and Shanxi will be affected by the dust, said the National Meteorological Center.

Parts of Inner Mongolia, Qinghai and Xinjiang will be swept by sandstorms.

The authorities suggested people in the affected regions close their doors and windows at home and wear masks outdoors.

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