BEIJING (AP) -- Chinese weather specialists used chemicals to engineer Beijing's heaviest rainfall of the year, helping to relieve drought and rinse dust from China's capital, the official Xinhua News Agency reported Friday.

Technicians with the Beijing Weather Modification Office fired seven rocket shells containing 163 cigarette-size sticks of silver iodide over the city's skies on Thursday, Xinhua said.

The reaction that occurred brought as much as four-tenths of an inch of rain, the heaviest rainfall this year, helping to "alleviate drought, add soil moisture and remove dust from the air for better air quality," Xinhua said.

Though unusual in many parts of the world, China has been tinkering with artificial rainmaking for decades, using it frequently in the drought-plagued north. Last month, another artificial rainfall was generated to clear Beijing after the city suffered some of the fiercest dust storms this decade.

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Whether cloud-seeding actually works has been the subject of debate in the scientific community. In 2003, the U.S. National Academy of Sciences questioned the science behind it as "too weak."