It was windy in Beijing two days ago, and the Meteorological Bureau said it was not a sandstorm. So what is the definition of sandstorm?

Dust weather includes floating dust, sand blowing, sandstorm and strong sandstorm, which are mainly classified by horizontal visibility: dust and fine sand float evenly in the air, so that the horizontal visibility is less than 10 km; Sand blowing: a weather phenomenon in which the wind blows up dust on the ground, making the air quite turbid and the horizontal visibility is within the range of 1 km to1km; Sandstorm: a weather phenomenon in which strong winds blow up a lot of dust on the ground, making the air very turbid and the horizontal visibility is less than 1 km; Strong sandstorm: a weather phenomenon in which strong winds blow up dust on the ground, making the air fuzzy and turbid, and the horizontal visibility is less than 500 meters.