What city earned the nickname the and ldquoSmoky City and because of its pollution?

The city that earned the nickname "Smoky City" is Pittsburgh, Pennsylvania. This nickname arose during the industrial era, particularly in the late 19th and early 20th centuries, when the city was a hub for steel manufacturing and coal production. The heavy use of coal for fuel and industrial processes led to significant air pollution, resulting in a smoggy, smoky atmosphere that contributed to the city's reputation. Efforts to clean up the environment have since improved air quality significantly in Pittsburgh.