This document discusses water pollution, its causes, types, effects, and prevention methods. It defines water pollution as contamination of water bodies that makes water harmful to humans and aquatic life. The two main sources are point source pollution from specific locations like factories, and non-point source pollution from diffuse sources like agricultural runoff. Water pollution kills aquatic animals, disrupts food chains, spreads diseases, and destroys ecosystems. Prevention methods include proper waste disposal, reducing water and chemical usage, and wastewater treatment.