Answer:
Hydrofluorocarbons
Step-by-step explanation:
Earlier chlorofluorocarbons were used for refrigeration purpose. But they were banned as they were primary cause of ozone depletion.
In order to replace chlorofluorocarbons, now hydrofluorocarbons are used which helps to protect earth from stratospheric ozone-depleting substances.
The difference between chlorofluorocarbons and hydrofluorocarbons is of hydrogen. In hydrofluorocarbons one of the halogen is being replaced by hydrogen.