Shanghai, China’s commercial and industrial hub, staged a massive cleanup for the World Expo, which began May 1 and is expected to draw up to 70 million people. It razed old steel mills and shipyards to make way for the Expo along the banks of the Huangpu River and closed down heavily polluting factories, or moved them to distant suburbs.The city also has sought to reduce car emissions by raising standards required of vehicles that travel into the city’s center. But cleaning up the city is only half the battle, since Shanghai lies downwind of heavily industrialized regions further inland. At times, farm fields in neighboring provinces are burned to clear stubble, leaving the city enveloped in a mucky haze.
