The delicate balance of $CO_2$ and $O_2$ is $NOT$ disturbed by:

Use of chlorofluorocarbons is not encouraged because

Mention the harmful effect of ultra violet radiations.

The pair of gases responsible for acid rain are

$A.$ Ammonium salts produce haze in the atmosphere.
$B.$ Ozone is produced when atmospheric oxygen reacts with chlorine radicals.
$C.$ Polychlorinated biphenyls act as cleansing solvents.
$D.$ 'Blue baby' syndrome occurs due to the presence of excess nitrate ions in water.
Choose the correct answer from the options given below:

Chlorine atoms act as catalysts in the depletion of the ozone layer in the Earth's atmosphere. These chlorine atoms originate from which of the following?