Define Pollutant .

Explanation

**Step-by-Step Text Solution:**

1. **Understanding Pollution**: First, we need to understand what pollution is. Pollution refers to the introduction of harmful substances or products into the environment, which can cause adverse effects on living organisms and the ecosystem.

2. **Defining Pollutant**: A pollutant is any material or action that contributes to pollution. This can be a substance that is released into the environment or an activity that causes harmful effects.

3. **Sources of Pollutants**: Pollutants can originate from human activities, such as industrial processes, vehicle emissions, and waste disposal. They can also come from natural sources, like volcanic eruptions or wildfires.

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