Water pollution occurs when harmful substances such as sewage, industrial waste, pesticides, and plastics enter water bodies. This contamination degrades water quality and poses severe risks to human health, causing diseases like cholera, dysentery, and typhoid. Polluted water also harms aquatic ecosystems by reducing oxygen levels, leading to fish deaths and loss of biodiversity. Toxic chemicals accumulate in the food chain through bioaccumulation and biomagnification, affecting both wildlife and humans. Long-term water pollution threatens freshwater availability, food security, and sustainable livelihoods.