Authorities in several provinces, including Baghdad, ordered government offices to shut, while schools nationwide were closed due to the eighth dust storm to have lashed the country since mid-April.
Another sandstorm in climate-stressed Iraq has sent at least 4,000 people to hospital with breathing problems and led to the closure of airports, schools and public offices across the country.
A thick cloud of dust on Monday enveloped the capital Baghdad and blanketed many other cities, including the Shia shrine city of Najaf to the south and Sulaymaniyah in the semi-autonomous Kurdish region.
Yellow and orange sand covered building roofs, cars and even crept into homes. Authorities in seven of Iraq's 18 provinces, including Baghdad, ordered government offices to shut.
But health facilities remained open to assist those most at risk, including the elderly and people suffering from chronic respiratory diseases and heart ailments.
At least 4,000 people were admitted to hospital needing treatment for respiratory difficulties, health ministry spokesperson Seif al Badr said, adding that all cases "received the necessary medical care".
It is the eighth dust storm since mid-April to hit Iraq, which has been battered by soil degradation, intense droughts and low rainfall linked to climate change.
The last one earlier this month led to the death of one person, while more than 5,000 others had to be hospitalised for respiratory problems.
Schools closed, flights affected
The sandstorm drastically reduced visibility to just 300 metres at Baghdad airport, prompting authorities to close airspace and halt flights, state-run INA news agency reported.
Airports in Najaf and Sulaymaniyah were also closed for the day.
Schools nationwide were also shuttered and end of year exams postponed to Tuesday. Universities also delayed exams.
At least 75 people with breathing problems were admitted to Baghdad's Sheikh Zayed Hospital, said Talib Abdelmoneim Nejm, one of the ICU officials.
The Middle East has always been battered by sandstorms, but they have become more frequent and intense. The trend has been associated with overuse of river water, more dams, overgrazing and deforestation.
Iraq is rich in oil and is known in Arabic as the land of the two rivers — in reference to the legendary Tigris and Euphrates rivers.
But the supply of water has been declining for years and Iraq is classified as one of the world's five countries most vulnerable to climate change and desertification.