पाण्याचे उष्णता प्रदूषण __________ यामुळे होते.

The correct answer is Option C (Industrial effluents).

Key Points:
• Thermal Pollution in Aquatic Ecosystems:
• Primary Source: Industrial effluents and cooling discharge from thermal power stations, nuclear power plants, steel mills, and petroleum refineries. These facilities draw cold water from natural rivers or lakes for condenser cooling and discharge large volumes of hot coolant wastewater back into the water bodies.
• Ecological Consequences:
• Dissolved Oxygen (DO) Depletion: Warm water has a lower saturation solubility for oxygen.
• Thermal Shock: Causes direct mortality of fish and aquatic organisms, alters metabolic rates, and triggers harmful algal blooms.
• Sewage, agrochemicals, and detergents contribute to organic/nutrient water pollution (eutrophication), not thermal pollution.
• Cooling towers and artificial cooling ponds are standard engineering remedies.
• Key Takeaway: Thermal water pollution is caused by the discharge of hot industrial effluents and cooling wastewater.