People in Hohhot, North China's Inner Mongolia Autonomous Region wrap scarves around their heads as the city is engulfed in sandstorms on April 10, 2023. Photo: IC

The latest round of sandstorms buffeting North China had covered 2.29 million square kilometers and affected 409 million people as of Tuesday morning, according to meteorological authorities.

Heavy sandstorms that engulfed the Chinese capital Beijing and other northern regions such as Inner Mongolia, Heilongjiang and Xinjiang originated from the southern part of Mongolia, as well as central and western parts of China's Inner Mongolia, affecting 15 provincial-level regions and 409 million people as of Tuesday morning, the National Forestry and Grassland Administration (NFGA) said in a bulletin sent to the Global Times.

The hashtag #sandstorm has been trending on Chinese social media since Monday evening, when some netizens complained the yellow smog had turned their cities orange. Several Beijing residents joked as they arrived at work on Tuesday morning that they had become colorless clay figures like the Terra-Cotta Warriors.

The National Meteorological Center (NMC) issued a blue alert for sandstorms on Tuesday, saying that most areas above the Yangtze River will be suffering from floating dust from Tuesday to Wednesday, and it called on the public to reduce outside activities. 

The affected areas stretch as far south as Shanghai, said the center. Shanghai is expected to witness floating dust from Tuesday night to Wednesday at noon, and the city will suffer short periods of heavy pollution during this time period, according to the city's weather department.

More than 1,000 locations on Blue Map App, one of China's public environmental databases, showed off-the-chart air pollution as of Tuesday morning, Ma Jun, founder of the app and director of the Beijing-based Institute of Public and Environmental Affairs, told the Global Times. 

Beijing on Tuesday afternoon lifted the yellow alert for sandstorms it issued on Monday, as visibility gradually improved in the capital. 

The NMC said on Sunday that this year, northern China has experienced more frequent sandstorms than average compared with the past 10 years. A total of eight sandstorms have hit northern China since January, according to local media reports.

According to the NFGA bulletin, the sandstorms were triggered by strong winds that were generated by a localized cyclone and a ground level cold front. The rapidly rising temperature over the previous week provided thermal conditions for sand to be lifted off the surface in large quantities. Moreover, sparse rainfall in Mongolia and some areas in China made conditions even more prone to sandstorm weather events.

Gui Hailin, an expert from the NMC, said that the incidence of more frequent sandstorms this year does not indicate that China has entered an active period of sandstorms. Since 2000, sandstorms have become less frequent in China overall. However, in recent years, some parts of the country have seen an uptick in sandstorms. 

Gui said there are many factors that can cause sandstorms, such as forestation, precipitation and temperature.

For years, China has been devoted to afforestation and addressing desertification in northern parts of the country, especially in Inner Mongolia, which borders Mongolia. However, environmental experts said that planting trees alone won't make sandstorms disappear. 

Protective forests have greatly reduced the frequency of sandstorms that originated within Chinese borders, however, they are less effective in face of the dusty winds from other countries, said Gui. 

Ma explained that forest shelterbelts won't be effective if sand was brought to the upper air, far exceeding their prevention scope. 

Experts said the current situation highlighted the urgency of China and Mongolia to continue doubling down on their joint efforts to combat desertification.

Last year, China and Mongolia signed bilateral documents in jointly addressing climate change, desertification and other areas. China held an online seminar to share with Mongolia its experience in addressing desertification in Kubuqi Desert in China's Inner Mongolia Autonomous Region. 

A sandstorm is a natural phenomenon that knows no boundaries and can be transmitted via all kinds of routes, said Ma. He said that addressing the problem requires transparent sharing of information and mutual trust, as well as joint efforts from countries in the region.