A sandstorm sweeping across much of northern China left the city in an orange fog and helped push air quality levels in the capital to the worst since 2017.

Beijings government issued a yellow alert, the first sandstorm warning this year. The Air Quality Index surged to 500, well above

health emergency levels, and a thick orange haze limited visibility to less than 1,000 meters (3,280 feet) Monday morning. Chinese social media was rife with pictures of the citys iconic buildings enveloped by the dust, with many users saying its the worst sandstorm in years.

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Levels of ultra-fine particulates in the air in Beijing surged to as high as 680 micrograms per cubic meter, the highest concentration since May 2017, according to records kept by the U.S. embassy there. Concentrations of slightly larger particles more commonly associated with sand surged to more than

2,000 per cubic meter at some monitoring stations.

Even before the storm, Beijings air quality had been

worsening as the nations economy roared back from the pandemic, thanks to a heavy-industry led recovery that saw steel and cement production surge and a jump in fossil fuel consumption.

The storm, which will continue for a day in Beijing,

originated in Mongolia and has also swept across northern provinces of Shaanxi, Shanxi and Hebei. Inner Mongolias Baotou city

canceled school classes because of the airborne dust.

Sandstorms often hit northern China, with deforestation and drought at least partly to blame. The government has launched massive

tree-planting projects to try to curb the storms since the 1970s. The Three-North Shelter Forest Program, which protects regions affected by sandstorms sweeping out of the Gobi Desert, aims to grow new trees on 35 million hectares (87 million acres) by 2050.

A residential building during a sandstorm in Beijing, March 15.

Photographer: Yan Cong/Bloomberg

The efforts seem to be having some success, with the annual number of sandy days in Beijing falling from 26 in the 1950s to around three after 2010, according to


Sandstorms typically occur in the spring and early summer, when the wind blows from the north. Last year, northern China experienced seven of them, with conditions lasting on average less than three days, according to the

China Climate Bulletin released by the National Climate Center. Thats fewer storms for a shorter duration than usual, it said.

With assistance by John Liu, and Karoline Kan

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