He immediately impressed me as an enlightened person, bright and funny. Upon entering the plant, I was amazed at how clean and efficient it was, not the sooty place full of workers shoveling coal that I'd imagined. In fact, there was hardly anyone there. Christina meets with a worker at a coal-fired power plant in Xhangye, China. But the thick black smoke puffing out of the smokestack suggested another side of the coal story.
Black smoke means incomplete, inefficient burning.
I can't say for sure if Director Zhang's plant is inefficient, but on a nationwide level, China has some problems. This is mostly due to emissions. Often, factory waste in China still contains so much coal that farmers cart it away to burn it again in their homes. The smoke created from burning coal pollutes the air with particles and gasses that contribute to smog, acid rain, global warming, and respiratory diseases like lung cancer and bronchitis. But some problems caused by China's coal use extend much farther than China itself.