What is air pollution ? What are the various reasons for air pollution ?

Explanation

### Step-by-Step Solution:

1. **Definition of Air Pollution**:
- Air pollution refers to the undesirable change in the quality of air in the atmosphere. This change is caused by the presence of harmful substances that can negatively affect the health of living beings and the environment.

2. **Understanding Pollution**:
- The term 'pollution' signifies an unwanted or harmful alteration in the natural state of something. In the case of air pollution, it means that the air we breathe is contaminated with harmful elements.

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