"The rapidly rising temperature over the previous week provided thermal conditions for sand to be lifted off the surface in large quantities," it said, adding the sparse rainfall in Mongolia and some areas in China "have made conditions even more prone to sandstorm weather events."
This year, the NMC said: "Northern China has experienced more frequent sandstorms than average compared to the recent 10 years."
Meanwhile, Chinese firefighters are engaged in "preventing flames of a grassland fire in Mongolia from spreading across the China-Mongolia border."