AA number of naturally occurring substances like Hydrogen Oxide (HOx), Methane(CH4), Hydrogen Gas (H2), Nitrogen Oxides (NOx) causes ozone layer depletion
BChlorine Monoxide (ClO); during volcanic eruptions, significant amount of chlorine may be released in the stratosphere which causes ozone layer depletion.
CTiny particulate matter in the stratosphere, known as stratospheric aerosols, the only matter protect ozone layer depletion.
DAny event, which release chlorine atoms into the atmospheric, can cause severe ozone destruction, because chlorine atoms in the stratosphere can destroy ozone very efficiently.