Freons are boon to industry, but curse to environment. Justify.

Explanation

Freons are fluorochlorocarbons (CFC). They are extensively used as foaming agents and are cheap. Hence, they are boon to industry.
Freons they get photolysed and produce chlorine free radicals. These radicals are very reactive with ozone and decrease the concentration of ozone in stratosphere. Hence they are curse to environment