Chattanooga faced a moment in truth in 1969 when Walter Cronkite declared the city to the most polluted in the nation.
Chattanooga had a heavy industrial base, and in 1969, unregulated emissions from industries, railroads and coal furnaces caused high concentrations of particulate matter. Determined to correct the situation the city approved the Air Pollution Control Ordinance in late 1969. By 1972 every major pollution source in Hamilton County was in compliance.
