The formation of ozone hole in the Antarctic region has been a cause of concern. What could be the…

Answer: (b) Presence of prominent polar front and stratospheric clouds; and inflow of chlorofluorocarbons.

The Antarctic ozone hole forms when CFCs reach the stratosphere. In the cold, isolated polar air, stratospheric clouds form and provide surfaces on which chlorine is freed from CFCs. Once sunlight returns, that chlorine destroys ozone. Option (b) is the only one that pairs the presence of stratospheric clouds with the inflow of CFCs. Its 'polar front' is a loose way of pointing to the polar circulation that isolates the air over Antarctica.

• ✓ (b) Stratospheric clouds form in the very cold air isolated over the pole in winter. They provide the surfaces for chlorine to break free from CFC molecules. Together with the inflow of CFCs, this explains the ozone hole.
• ✗ (a) The ozone loss happens in the stratosphere, not the troposphere. Tropospheric turbulence plays no part in the process, even though CFCs are involved.
• ✗ (c) The clouds are needed for the hole to form, so their absence would not cause it. Methane is not the ozone-destroying agent here; CFCs and halons are.
• ✗ (d) The hole depends on extremely low stratospheric temperatures, which allow the clouds to form. It does not depend on warming at the pole.

Remember · Antarctic ozone hole = CFC-derived chlorine + polar stratospheric clouds in the cold, isolated winter polar vortex; sunlight in spring triggers the ozone destruction. Montreal Protocol phases out CFCs.

📘 Read it in NCERT: Class 11 Fundamentals of Physical Geography, Ch 11 (practise this chapter)

Question: UPSC Civil Services (Preliminary) 2011, General Studies paper. Explanation: Minimalist IAS, checked 25 Oct 2026 (how we verify). · Report an error