People were told to stay at home and flights have been disrupted in parts of the Middle East after the latest in a series of unprecedented sandstorms swept across the region.
The storms have sent thousands of people in the Middle East to hospital in recent weeks, with at least one death in Iraq and three in Syria.
The nearly back-to-back sandstorms have also blanketed parts of Iran, Kuwait and Saudi Arabia.
Experts and officials are blaming climate change and poor governmental regulations.
Sandstorms are spurred by seasonal winds and are typical in late spring and summer.
However, this year they have occurred nearly every week in Iraq since March.
From the Saudi Arabian capital Riyadh to the Iranian capital Tehran, bright orange skies and a thick veil of grit signalled another stormy day in the Middle East on Monday.
Iraqi authorities declared the day a national holiday, urging government workers and residents to stay home in anticipation of the tenth storm to hit the country in the last two months.
The health ministry stockpiled cannisters of oxygen at facilities in hard-hit areas, according to a statement.
“Its a region-wide issue but each country has a different degree of vulnerability and weakness,” said Jaafar Jotheri, a geoarchaeologist at the University of Al-Qadisiyah in Baghdad.
In Syria, medical departments were put on alert as the sandstorm hit the eastern province of Deir el-Zour that borders Iraq, Syrian state TV said.
Earlier this month, a similar storm in the region left at least three people dead and hundreds were hospitalised with breathing problems.
Dr Bashar Shouaybi, head of the health ministry’s office in Deir el-Zour, told state TV that hospitals were prepared and ambulances were on standby.
He said they have acquired an additional 850 oxygen tanks and medicine needed to deal with patients who have asthma.
For the second time this month, Kuwait International Airport suspended all flights Monday because of the dust.
Video showed largely empty streets with poor visibility.
Saudi Arabia’s meteorological association reported that visibility would drop to zero on the roads in the capital Riyadh this week.
Officials warned drivers to go slowly.
Emergency rooms in the city were flooded with 1,285 patients this month complaining they could not breathe properly.
Iran last week shut down schools and government offices in the capital of Tehran over a sandstorm that swept the country.
It hit hardest in the nation’s southwest desert region of Khuzestan, where more than 800 people sought treatment for breathing difficulties.
Dozens of flights out of western Iran were cancelled or delayed.
Blame over the dust storms and heavy air pollution has mounted, with a prominent environmental expert telling local media that climate change, drought and government mismanagement of water resources are responsible for the increase in sandstorms.
Iran has drained its wetlands for farming – a common practice known to produce dust in the region.
Alireza Shariat, the head of an association of Iranian water engineers, told Iran’s semi-official ILNA news agency last month that he expected extensive dust storms to become an “annual springtime phenomenon” in a way Iran has never seen before.
In Iraq, desertification exacerbated by record-low rainfall is adding to the intensity of storms, said Mr Jotheri. In a low-lying country with plenty of desert regions, the impact is almost double, he said.
He added: “Because of 17 years of mismanagement of water and urbanization, Iraq lost more than two thirds of its green cover,” he said. “That is why Iraqis are complaining more than their neighbours about the sandstorms in their areas.”