Detergent is considered more pollutant than soap primarily because it contains synthetic chemicals and surfactants that do not biodegrade as easily as natural soap ingredients. Many detergents include phosphates, bleach, and other harmful additives that can accumulate in water bodies, leading to algal blooms and disrupting aquatic ecosystems. 

Additionally, the production and disposal of detergents often release pollutants into the air and water, exacerbating environmental degradation. In contrast, soap is typically made from natural fats and oils, making it more biodegradable and less harmful to the environment.