Question

What is behind the destruction of the ozone layer?

Answer 1

Chrolofluorocarbon (CFCs) is the main criminal.

Explanation:

Chrolofluorocarbons(CFCs) ,as known as Freon, are suspected to be the main reason for the destruction of ozone layer and we have decided to ban the usage of CFCs in Montreal Protocol(1987).
https://en.wikipedia.org/wiki/Montreal_Protocol

When CFCs are decomposed by UV, they form chlorine radical(`Cl*`) and react with ozone(`O_3`).

`O_3 -> O_2 + O*`
`O_3+ Cl* -> ClO* +O_2` (1)
`ClO* + O* -> Cl* +O_2` (2)

(1) and (2) are chain reactions. Thus, a small amount of `Cl` radical may destroy much more `O_3` molecules. How awful!