The contamination of air by adding gases, smoke and ash is called ______

Explanation

**Step-by-Step Solution:**

1. **Understanding the Question**: The question asks about the contamination of air caused by the addition of gases, smoke, and ash.

2. **Identifying the Process**: When we add harmful substances like gases, smoke, and ash to the air, we are altering its natural state. This alteration is known as contamination.

3. **Defining Pollution**: The term that describes the introduction of harmful substances into the environment is "pollution." Pollution can occur in various forms, including air, water, and soil pollution.

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