Why is excessive use of CFCs a cause of concern?

Explanation

### Step-by-Step Solution:

1. **Definition of CFCs**:
- CFCs stand for Chlorofluorocarbons, which are chemical compounds that were commonly used in refrigeration, air conditioning, and aerosol propellants.

2. **Impact on Ozone Layer**:
- The excessive use of CFCs leads to the depletion of the ozone layer. CFCs release chlorine atoms when they are broken down in the stratosphere, which then reacts with ozone (O₃) molecules.

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