Thermal pollution is the sudden increase or decrease in the temperature of a water body due to human activities. Thermal pollution is mainly caused by industries taking in water from natural sources and releasing it back at an altered temperature. Other human factors like deforestation and soil erosion are also responsible for thermal pollution. The warm temperature of the water decreases the dissolved oxygen concentration in water bodies resulting in the death of many aquatic plants and animals. It also increases the metabolic rate of aquatic organisms, thus disrupting the food chain.