The municipal meteorological authorities created artificial rainfall in most parts of the city on Monday hoping to brighten its sky that turned yellow with 300,000 tons of sand from the China-Mongolia border, said Zhang Mingying, a spokesperson with Beijing Municipal Meteorological Bureau.

When the eighth, as well as the worst, sandstorm of the year attacked from outside Beijing on Monday, experts estimated an average 20 grams of sand fell on every single square meter of land.

The city government sent more than 300 sprinklers to clean at least 500 urban roads, covering an area of 30 million square meters, the city's environment watchdog said.

Sand has seriously contaminated Beijing's air, which is seriously polluted in the recent two days according to the monitoring center of the city's environment protection bureau.

The sandy weather is challenging the city's"blue sky" campaignas Beijing has seen azure, unpolluted sky on only five of the past 18 days.

Du Shaozhong, vice director of the municipal environment protection bureau, said more efforts are called for from all walks of life to clean Beijing's sky, an increasingly difficult job amid fast economic growth and its heavy burdens on the environment.

"We need to work harder to create more blue sky days instead of sitting back and relying solely on the weather," said Du.

Besides sandstorms, he said the side effects of Beijing's fast urban development, including tail gas and industrial emission, has also burdened its environment.

The latest meteorological report said the sand might be swept away as the wind scale is to reach five or six Tuesday night and Wednesday, but no significant rainfall will ease the city's thirstin the coming three or four days.

But the central meteorological station on Tuesday predicted sand will hover over north China's sky for another two or three days, a bad omen for Beijing.

North China has experienced 10 sandstorms this spring and more are to come in April and May, said Qiao Lin, the station's senior engineer.

Though most citizens are depressed at the sandy weather, taxi drivers are quite happy about it.

"I'm busier than usual," said Hu Jianjun, a driver from YinjianTaxi Co., one of the biggest taxi firms in Beijing."I rely on the weather a lot. For me, rain, snow, hailstones, mid-summer sauna-like weather and now sand all make fortune." Enditem