​Which of the following is the best action to increase the thickness of the ozone layer?​

Correct option is A

The correct answer is (A) Reduce use of fluorine-based refrigerants.

• Reducing the use of fluorine-based refrigerants is the best action to increase the thickness of the ozone layer. 

Explanation:

• Ozone-depleting substances (ODSs): Gases containing chlorine and bromine atoms, such as those found in refrigerators and air conditioners, deplete the ozone layer. 
• Montreal Protocol: This global agreement, finalized in 1987, aims to protect the ozone layer by reducing the production and consumption of ODSs. 
• Ozone layer recovery: The ozone layer is expected to return to normal levels by around 2050. However, delays in ending the use of ODSs could cause further damage and prolong recovery. 
• Refrigerant handling licenses: Licensed technicians can help minimize the emission of refrigerants into the atmosphere.