Industrialization caused a lot of environmental problems. For more than 200 years a great pall of coal smoke hung over most industrial cities, while toxic dust shortened the lives of miners and mill workers. The rivers that flowed through industrial cities were so polluted that no fish could live in them. The smell of the Chicago stock yards nauseated generations of residents and visitors. When citizens’ environmental groups protested against these conditions in the 1960s and 1970s, Congress responded by passing clean air and clean water acts. Industrialists warned that complying with these new laws would be ruinously expensive, but they were wrong. In the years since 1970, we have enjoyed a combination of better environmental conditions and continued economic growth. Grave environmental problems still confront us–including climate change–but the same ingenuity that led to the great industrial advances is now leading to inventions that will mitigate the environmental problems they caused.