The 1948 Donora smog was a historic air inversion resulting in a wall of smog that killed 20 people and sickened 7,000 more in Donora, Pennsylvania, a mill town on the Monongahela River, 24 miles (39 km) southeast of Pittsburgh. The event is the basis of the Donora Smog Museum. Sixty years later, the incident was described by The New York Times as "one of the worst air pollution disasters in the nation's history". Even ten years after the incident, mortality rates in Donora were significantly higher than those in other communities nearby.