The Montreal Protocol and its subsequent amendments have resulted in reduced ozone depletion. It is also observed that ozone depletion over the South Pole is much more severe than over the North Pole. In this regard, consider the following statements:

A. A polar vortex is formed around the North Pole.
B. Stratospheric temperatures over the South Pole are much lower compared to the North Pole.
C. Emissions of ozone depleting substances are higher in the southern hemisphere compared to the northern hemisphere.
D. More extensive formation of polar stratospheric clouds occurs over the South Pole compared to the North Pole.

Which one of the following options includes the correct combination of statements that explain the difference in the ozone depletion between the poles?

Correct option is B

Explanation-

Statement A - A polar vortex is formed around the North Pole.
TRUE, but incomplete in this context.
Polar vortices form at both poles. However, the vortex in the South Pole is stronger, more stable, and lasts longer, leading to more extensive ozone depletion. So while this statement is technically true, it doesn’t explain why ozone depletion is more severe in the South.

Statement B - Stratospheric temperatures over the South Pole are much lower compared to the North Pole.
 TRUE.
The Antarctic (South Pole) has colder stratospheric temperatures, which facilitates the formation of polar stratospheric clouds (PSCs). These PSCs are crucial for ozone-depleting reactions to occur. This is a major reason why the ozone hole is more prominent over the South Pole.

Statement C - Emissions of ozone depleting substances are higher in the southern hemisphere compared to northern hemisphere.
FALSE.
Most ozone-depleting substances (ODS), like CFCs, have been emitted more in the Northern Hemisphere due to greater industrial activity. The greater ozone depletion in the Southern Hemisphere is not due to higher emissions, but due to climatic and atmospheric conditions (like colder temperatures and stronger polar vortex).
​
Statement D - More extensive formation of polar stratospheric clouds over the South Pole compared to the North Pole.
TRUE.
PSCs form under very cold stratospheric conditions. Since the South Pole has colder and more stable conditions, PSC formation is more extensive. This leads to greater catalytic destruction of ozone.

So, correct answer is Option (b) – B and D