The detergents used in olden days caused pollution in rivers and waterways. Comment. 

Explanation

Earlier used detergents have great deal of branching in their hydrocarbon tails. The detergent molecules associate with branched chain hydrocarbon tails. These side chains stop bacteria from attacking and breaking. This results in slow degradation of detergent molecules and leads to the accumulation of detergent molecule. This causes pollution in rivers and waterways.