Answer: Reduced Destruction or Depletion of the ozone layer
Explanation: Chlorofluorocarbons known as CFCs ( chlorine, fluorine and carbon) are harmful to the ozone layer i.e it deplete the ozone layer in the stratosphere of the atmosphere which protects the earth from ultraviolet rays. Chlorofluorocarbons are pretty stable compound, so it is accumulated over time as it raises to the atmosphere to react with the ozone molecules and eventually destroys it (ozone layer). As the ozone layer gets destroyed, the earth surface is no longer protected from harmful UV rays (UVB) which reaches down and breaks down DNA of organisms, although some of these DNA gets repaired automatically but others don't and this leads to the formation of cancer cells.
So reduction in the destruction or depletion of the ozone layer is the goal being achieved in banning Chlorofluorocarbons.