Select the incorrect statement regarding the ozone.

Options

A. Ozone gas continuously formed by the action of UV rays on elementary oxygen and also degraded into molecular oxygen in the stratosphere.
B. The thickness of the ozone in a column of air from the ground to the top of the atmosphere is measured in terms of Decibels units.
C. Cl degrades ozone releasing molecular oxygen, with these atoms acting merely as catalysts.
D. Although ozone depletion is occurring widely in the stratosphere, the depletion is particularly marked over the antarctic region.

Answer

To solve the question regarding the incorrect statement about ozone, we will analyze each statement provided in the question.

### Step-by-Step Solution:

1. **Understanding Ozone Formation and Degradation**:
- Ozone (O₃) is formed in the stratosphere when ultraviolet (UV) rays from the sun act on molecular oxygen (O₂). This process creates ozone, which plays a crucial role in absorbing harmful UV radiation.
- Ozone is also degraded back into molecular oxygen, maintaining a balance in the stratosphere.

**Hint**: Remember the role of UV rays in the formation of ozone and the balance between formation and degradation.

2. **Evaluating the Thickness Measurement of Ozone**:
- The thickness of the ozone layer is often measured in Dobson Units (DU), not decibels (dB). This is a common misconception.
- Therefore, if a statement claims that the thickness is measured in decibel units, it is incorrect.

**Hint**: Focus on the units used for measuring ozone thickness; they are not decibels.

3. **Chlorine and Ozone Depletion**:
- Chlorofluorocarbons (CFCs) release chlorine atoms when they break down in the stratosphere. These chlorine atoms act as catalysts in the degradation of ozone, leading to ozone depletion.
- This statement is correct as it describes the mechanism of ozone depletion accurately.

**Hint**: Recall the impact of CFCs and chlorine on ozone depletion.

4. **Ozone Depletion in the Antarctic Region**:
- It is well-documented that ozone depletion is particularly severe over the Antarctic region, leading to the formation of the "ozone hole."
- This statement is also correct and reflects current scientific understanding.

**Hint**: Consider the geographical aspects of ozone depletion, especially in relation to the Antarctic.

5. **Identifying the Incorrect Statement**:
- After evaluating all the statements, the second statement regarding the measurement of ozone thickness in decibel units is the only incorrect statement. It should be in Dobson Units.

**Final Answer**: The incorrect statement regarding ozone is that its thickness is measured in decibel units.

### Summary:
- The incorrect statement is about the measurement units for ozone thickness, which should be Dobson Units (DU) instead of decibels (dB).