Businesses in Baghdad closed during the blinding storm as reduced visibilities delayed air traffic in and out of the capital.

Local news reports said that many Iraqis considered the storm to be the worst in living memory.

The massive cloud of desert sand eventually spread eastward into Iran, where officials declared a two-day public holiday because of the unhealthful air quality.

Many Tehran residents were said to have taken advantage of the holiday by leaving the city for provinces that had cleaner air.

The fine particles in the atmosphere acted as a color filter that actually caused a “blue moon” to appear over Tehran.

While the region has long suffered blinding sandstorms, several years of drought have created conditions that resulted in this summer’s near-record storm.

The Iraqi desert has been made even more arid by the diversion of the Tigris and Euphrates rivers for agricultural and municipal use upstream in countries like Turkey.

Resulting water shortages downstream made the landscape dry out and become more dusty.

Photo: NASA Earth Observatory