The term "water-pollution" can be defined in several ways. Which of the following statements does not give the correct definition ?

Options

A. The addition of undesirabel substances to water-bodies
B. The removal of desirable substances from water-bodies
C. A change in pressure of the water-bodies
D. A change in temperature of the water-bodies

Explanation

To determine which statement does not correctly define "water pollution," we will analyze each statement provided in the question.

### Step-by-Step Solution:

1. **Understanding Water Pollution**: Water pollution refers to the contamination of water bodies (like rivers, lakes, oceans) due to the introduction of harmful substances or the removal of beneficial substances.

2. **Analyzing Statement A**:
- **Statement**: "The addition of undesirable substances to water bodies."
- **Analysis**: This statement correctly defines water pollution as it mentions the introduction of harmful (undesirable) substances, which is a key aspect of water pollution.
- **Conclusion**: This statement is correct.

3. **Analyzing Statement B**:
- **Statement**: "The removal of desirable substances from water bodies."
- **Analysis**: This statement also aligns with the definition of water pollution. Removing beneficial substances can lead to an imbalance in the ecosystem, which can be considered a form of pollution.
- **Conclusion**: This statement is correct.

4. **Analyzing Statement C**:
- **Statement**: "A change in pressure of the water body."
- **Analysis**: A change in pressure does not necessarily indicate contamination or pollution. It can occur due to physical factors but does not directly relate to the introduction of harmful substances or the removal of beneficial ones.
- **Conclusion**: This statement does not define water pollution correctly.

5. **Analyzing Statement D**:
- **Statement**: "A change in temperature of the water bodies."
- **Analysis**: Changes in temperature can result from the introduction of waste materials (like industrial effluents) and can affect aquatic life, thus relating to water pollution.
- **Conclusion**: This statement is correct.

### Final Conclusion:
The statement that does not give the correct definition of water pollution is **Statement C**: "A change in pressure of the water body."

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