Ozone hole is a region over:

The correct answer is  the Antarctic caused mainly by CFC gases.

Key PointsOzone Hole and Its Causes

• Ozone Layer: The ozone layer is a region of Earth's stratosphere that contains a high concentration of ozone (O₃) molecules. It absorbs most of the Sun's harmful ultraviolet radiation.
• Location: The ozone hole primarily occurs over the Antarctic region.
• Causes: The primary cause of the ozone hole is the emission of chlorofluorocarbons (CFCs) and other ozone-depleting substances. These compounds release chlorine and bromine atoms upon exposure to ultraviolet light, which then catalytically destroy ozone molecules.
• Mechanism: During the winter, polar stratospheric clouds (PSCs) form in the cold stratosphere over Antarctica. These clouds provide a surface for chemical reactions that produce chlorine and bromine gases. When sunlight returns to the region in the spring, these gases rapidly deplete the ozone layer.
• Environmental Impact: The depletion of the ozone layer leads to increased UV radiation reaching the Earth's surface, which can cause skin cancer, cataracts, and other health issues, as well as negatively impact ecosystems and wildlife.

Additional Information

• Montreal Protocol: The Montreal Protocol on Substances that Deplete the Ozone Layer is an international treaty designed to phase out the production and consumption of ozone-depleting substances, including CFCs. It was signed in 1987 and has been successful in reducing the emissions of these harmful chemicals.
• Recovery: Thanks to international efforts and regulations, the ozone layer is showing signs of recovery. Scientists predict that the ozone layer will return to its pre-1980 levels by the middle of the 21st century.
• Polar Stratospheric Clouds (PSCs): These clouds play a crucial role in the formation of the ozone hole. PSCs form at very low temperatures and provide a surface for chemical reactions that release chlorine and bromine atoms, which then deplete ozone.
• Health and Environmental Effects: Increased UV radiation due to ozone depletion can lead to higher incidences of skin cancer and cataracts in humans. It can also affect marine ecosystems, particularly plankton, and disrupt the food chain.
• Climate Change: While CFCs are potent greenhouse gases, their phase-out under the Montreal Protocol has also contributed to mitigating climate change. However, other greenhouse gases continue to drive global warming.