The Montreal Protocol refers to:

Good ozone and bad ozone are found in $.........$ respectively.

The Montreal Protocol aims at:

The Montreal Protocol was signed to:

Which of the following statement$(s)$ is/are correct?
$(i)$ The Montreal Protocol was signed in $1987$ and became effective in $1989$.
$(ii)$ 'Good' ozone is found in the troposphere.
$(iii)$ Ozone is formed by the action of $UV$ rays on molecular oxygen and degrades into molecular oxygen.
$(iv)$ $CFCs$ are responsible for the imbalance between the production and degradation of ozone.
$(v)$ $DNA$ and proteins of living organisms absorb $UV$ rays.

What are the chief pollutants of the atmosphere that are most likely to deplete the ozone layer?