Which day is celebrated as International day for preservation of Ozone layer?

Explanation

### Step-by-Step Text Solution:

1. **Understanding the Ozone Layer**: The ozone layer, also known as O3, is a protective layer present in the stratosphere of the Earth's atmosphere. It plays a crucial role in shielding the Earth from harmful ultraviolet (UV) radiation.

2. **Importance of the Ozone Layer**: The ozone layer is essential for protecting living organisms from the damaging effects of UV radiation, which can lead to health issues such as skin cancer and cataracts, as well as environmental impacts.

3. **Threats to the Ozone Layer**: Over the years, human activities have contributed to the depletion of the ozone layer. Certain chemicals, particularly chlorofluorocarbons (CFCs), have been identified as significant contributors to this depletion.

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