A dust storm or sandstorm is a meteorological phenomenon common in arid and semi-arid regions. Dust storms arise when a gust front blows loose sand and dust from a dry surface. Particles are transported by saltation and suspension, causing soil erosion from one place and deposition in another. The Sahara and drylands around the Arabian peninsula are the main source of airborne dust, with some contributions from Iran, Pakistan and India into the Arabian Sea, and China.
Dust Storm, Rajasthan, India. (This setting was the inspiration for Arinn Dembo's short story "Monsoon". I haven't read it, but since I'm repinning from her, and she pins the coolest stuff, I figured I'd include that part of her caption.)