Pollution is not caused by

Options

A. Thermal power plant
B. Automobile
C. Radioactive power plant
D. Hydroelectric power plant

Answer

To solve the question "Pollution is not caused by," we need to evaluate each of the given options and determine which one does not contribute to pollution.

### Step-by-Step Solution:

1. **Evaluate Thermal Power Plant**:
- Thermal power plants burn fossil fuels (like coal) to generate electricity.
- This process releases various pollutants into the atmosphere, including sulfur dioxide, carbon monoxide, and nitrogen oxides.
- **Conclusion**: Thermal power plants cause pollution.

2. **Evaluate Automobile**:
- Automobiles burn fuel (petrol or diesel) to operate.
- This combustion process emits pollutants such as carbon monoxide, nitrogen oxides, and other harmful substances.
- **Conclusion**: Automobiles cause pollution.

3. **Evaluate Radioactive Power Plant**:
- Radioactive power plants, which utilize nuclear energy, produce radioactive waste as a byproduct.
- This waste can remain hazardous for thousands of years and poses significant environmental and health risks.
- **Conclusion**: Radioactive power plants cause pollution.

4. **Evaluate Hydroelectric Power Plant**:
- Hydroelectric power plants generate electricity by harnessing the energy of flowing water.
- This process does not involve burning fossil fuels or releasing harmful emissions into the atmosphere.
- Hydropower is considered a renewable energy source as it utilizes the Earth's water cycle.
- **Conclusion**: Hydroelectric power plants do not cause pollution.

### Final Answer:
The option that does not cause pollution is **hydroelectric power plant**.

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