Harmful algal blooms, often referred to as 'red tides' or 'eutrophication', occur when excessive nutrients enter aquatic ecosystems. Nutrient discharge from estuaries carries agricultural runoff and sewage, fueling algal growth. Monsoon run-off similarly transports fertilizers and organic matter from land into coastal waters. While upwelling itself is a process that brings nutrient-rich deep water to the surface, which can support marine life, in specific conditions and when combined with excess nutrients from anthropogenic sources, it can exacerbate algal bloom formation. Therefore, all three factors can contribute to increased harmful algal blooms.