CHINA DUST STORMS

A visitor to the Badaling Great Wall of China near Beijing covers his nose in reaction to a severe dust storm that reduced visibility greatly on Wednesday, March 20, 2002. Dust storms choke northern China nearly every spring, often blown off the dry expanses of the Mongolian desert plain. The first "shachenbao," or "sand-dust tempest," of 2002 struck Beijing this weekend.(AP Photo/Ng Han Guan)