The largest source of air pollution is:

Options

A. thermal power plants
B. industries
C. transportation
D. refuse disposal

Answer

**Step-by-Step Solution:**

1. **Understanding Air Pollution**:
- Air pollution refers to the presence of harmful substances in the atmosphere that can adversely affect human health and the environment.

2. **Identifying Sources of Air Pollution**:
- There are various sources of air pollution, including industrial emissions, vehicle exhaust, and waste disposal. However, not all sources contribute equally to air pollution.

3. **Analyzing Major Contributors**:
- Among the various sources, thermal power plants are significant contributors to air pollution. They burn fossil fuels, which release a large amount of harmful gases into the atmosphere.

4. **Conclusion**:
- Based on the analysis, the largest source of air pollution is identified as thermal power plants due to their extensive release of harmful gases.

**Final Answer**: The largest source of air pollution is thermal power plants.

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