6. Philadelphia, PA
Major Causes of Pollution: 4 (River Dumping, Traffic Congestion, Abandoned Buildings, Abandoned Neighborhoods)
The Delaware River near Philadelphia is considered as one of the dirtiest rivers in America. Philadelphia also does no favors by heavily contributing to other aspects when it comes to pollution. The city is heavily congested, and a lot of air pollution is released daily. There are also tens of thousands of abandoned homes and neighborhoods meaning that some areas in the city are left with neglect and trash fill those streets from every corner.
