All flights to and from airports in five cities in Northwest China's Gansu province - Wuwei, Jinchang, Zhangye, Jiuquan and Jiayuguan - have been canceled due to heavy sandstorms that hit the region on Monday, local authorities said.

Many cities in Gansu reported very poor visibility, with the lowest reaching up to 150 meters, when the region was struck by the heaviest sandstorms since 2002, according to the local meteorological bureau on Monday.

The cities of Jiuquan and Jiayuguan issued an orange warning signal for sandstorms, the second-highest in the three-tiered warning system, early Monday morning.

Authorities said the sandstorm and poor visibility would last till Tuesday in Gansu.

And in North China's Inner Mongolia autonomous region, the local meteorological department also issued an orange warning on Monday, requiring relevant departments and cities to take concrete and effective anti-disaster measures.

Local meteorological departments have forecasted the sandstorm will continue to hit the cities of Yinchuan, capital of Northwest China's Ningxia Hui autonomous region, and Shizuishan, and the northern part of Wuzhong and Zhongwei cities, with the lowest visibility reaching less than 500 meters till Tuesday.