What is the Montreal Protocol?

Which of the following is responsible for the depletion of the ozone layer?

In the stratosphere,which of the following elements acts as a catalyst in the degradation of ozone and the release of molecular oxygen?

The Montreal Protocol aims at:

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.

Identify the incorrect statement.