What #Pittsburgh Looked Like When It Decided It Had a #Pollution Problem - CityLab
▻http://www.citylab.com/design/2012/06/what-pittsburgh-looked-when-it-decided-it-had-pollution-problem/2185
In 1941, influenced by a similar policy introduced in St. Louis four years earlier, the city of Pittsburgh passed a law designed to reduce coal production in pursuit of cleaner air. Not willing to cripple such an important part of the local economy, it promised to clean the air by using treated local coal. The new policy ended up not being fully enacted until after World War II.