Water pollution occurs when harmful substances are introduced into water bodies, such as rivers, lakes, oceans, and groundwater, making it unsuitable for its intended purposes and harmful to ecosystems and human health. This contamination stems from various human activities like industrial discharge, agricultural runoff, improper waste disposal, sewage discharge, and oil spills.

Water pollution exacerbates water scarcity through several mechanisms. Firstly, it reduces the availability of clean water by contaminating water sources, necessitating extensive treatment to make it safe for consumption and agriculture. Secondly, pollution can lead to the loss of usable water sources as ecosystems and habitats are damaged, further restricting access to freshwater. Additionally, contamination of groundwater, a vital source for many communities, worsens scarcity as polluted aquifers become unusable. Lastly, pollution disrupts natural water cycles, altering precipitation patterns and evaporation rates, which can decrease water availability in affected regions.