BEIJING: Sandstorms whipping across China shrouded cities in an unhealthy cloud of sand and grit today, with winds carrying the pollution outside the mainland as far as the island of Taiwan.

It was the latest sign of the effects of desertification: Overgrazing, deforestation, urban sprawl and drought have expanded deserts in the country’s north and west. The shifting sands have gradually encroached onto populated areas and worsened sandstorms that strike cities, particularly in the spring.

Winds blowing from the northwest have been sweeping sand across the country since Saturday, affecting Xinjiang in the far west all the way to Beijing in the country’s east. The sand and dust were carried to parts of southern China and even to cities in Taiwan.

The sandstorm in Taiwan, 160 km from the mainland, forced people to cover their faces to avoid breathing in the grit that can cause chest discomfort and respiratory problems even in healthy people. Drivers complained their cars were covered in a layer of black soot in just 10 minutes.

The airport on the Taiwanese-controlled islet of Matsu, just off the

mainland coast, suspended services on Sunday due to poor visibility caused by the sandstorm.

Grit from Chinese sandstorms has been found to travel as far as South Korea, Japan and even the western United States. The sand that covered the city of Taipei on Sunday had mostly moved to the island’s south by Monday, and was expected to dissipate by Tuesday.

The latest sandstorms were the most severe in China in several years. A massive sandstorm hit Beijing in 2006, when winds dumped about 300,000 tonnes of sand on the capital.

The Central Meteorological Station urged people to close doors and windows, and cover their faces with masks or scarves when going outside. Sensitive electronic and mechanical equipment should be sealed off, the station said in a warning posted today on its Web site. China Central Television told viewers to clean out their noses with salt water and remove grit from ears with cotton swabs dipped in alcohol.

State television’s noon newscast showed the tourist city of Hangzhou on the eastern coast, where graceful bridges and waterside pagodas

were hidden in a mix of sand and other pollution. In Beijing, residents and tourists with faces covered scurried along sidewalks to minimise exposure to the pollution.

The US Embassy in Beijing warned that particulate matter in the air made conditions “hazardous,” though high winds dispersed some of the pollution and the air quality was later upgraded to “very unhealthy.”