The document discusses water pollution, specifically focusing on the Cuyahoga River fire of 1969. It describes how the river regularly caught fire due to severe pollution from industrial waste from nearby steel mills and businesses. The 1969 fire drew national attention and helped spur the environmental movement and passage of the Clean Water Act of 1972. The document also discusses different types of water pollution, including point source pollution from identifiable sources like factories, and non-point source pollution from diffuse sources like agricultural and urban/suburban runoff.