Main cause of ozone holes and its depletion is

The correct option is All of the above.

Ozone depletion and the formation of ozone holes are primarily caused by the release of synthetic chemical compounds known as Ozone Depleting Substances (ODSs). These substances release chlorine and bromine atoms into the stratosphere, which catalytically destroy ozone ($O_3$) molecules.
Let us examine the role of each of the options provided:

1. Propellants:
Aerosol cans and spray dispensers traditionally used Chlorofluorocarbons (CFCs) as propellants to push the product out of the container. When sprayed, these CFCs escape into the atmosphere and eventually reach the stratosphere, contributing significantly to ozone depletion.

2. Foam-blowing agents:
During the manufacture of plastic foams (such as polyurethane, polystyrene, and polyolefin foams used for insulation or packaging), blowing agents are used to create the cellular structure of the foam. Historically, CFCs and Hydrochlorofluorocarbons (HCFCs) were widely used as foam-blowing agents, releasing ozone-depleting chemicals into the air during production and usage.

3. Halocarbon refrigerants:
Refrigeration and air-conditioning systems relied heavily on halocarbon compounds, particularly CFCs (like Freon-12) and HCFCs, as refrigerants. Leakage from these systems, as well as improper disposal of old refrigerators and air conditioners, releases these stable compounds into the environment, where they migrate to the upper atmosphere and destroy ozone.

Since propellants, foam-blowing agents, and halocarbon refrigerants are all major commercial sources of the ozone-depleting halocarbons responsible for ozone holes, all three options are correct. Therefore, the main cause of ozone depletion is represented by All of the above.