Explanation:

• Supersonic jets flying in the stratospheric region produces water vapour, hydroxyl radical and oxides of nitrogen that  are responsible for depletion of ozone layer and formation of greenhouse gases. Most of the naturally occurring ozone occurs in the stratosphere. Almost about 90 percent of natural ozone occurs in the stratosphere. The ozone which is present in the stratosphere is very helpful as this protects the humans from theharmful rays and removes all the incoming UV rays and almost 70 percent of incoming UV rays from the equator and almost ninety percent of the rays from the poles.
• All the big aircraft produce carbon dioxide, water, CO Etc. Most of the commercial fights are confined to the troposphere. Most of the high-level supersonic aircraft produce harmful pollutants in the stratosphere.

Hence option 1st is correct.