In Southern China, everything is covered in a layer of dust (never paint a building white). The main reason for the dust is because the cities are still being built (every time I go back, there is a new giant building). As you travel around the Pearl River region, you will see giant cranes on the horizon, skeletons of buildings, and new roads being built. Guangzhou is constantly expanding outward (as are the cities of Dongguan, Shenzhen, Zhaoqing, Zhuhai, Foshan, Huizhou, and Zhongshan). Eventually, all of these cities will merge and China will have the world's largest "mega city" with a population of 42 million people. The numbers are mind blowing. I'm not sure if China's plans will work (they need better roads)... but the infrastructure, high speed rail lines, and public mass transport will hopefully reduce the need for cars.