Older refrigerants such as R12 (a CFC) and R22 (an HCFC) contain chlorine, which drifts into the upper atmosphere and breaks down ozone. Under the Montreal Protocol these gases were phased out in stages worldwide, including in India. ODP compares each gas with CFC-11: CFCs sit around 1, HCFCs well below that, and modern HFCs, HFOs, hydrocarbons and CO2 have an ODP of zero.
Today, practically every new commercial refrigerator and freezer uses a zero-ODP refrigerant, so ODP is no longer a real differentiator when comparing new equipment. The current concern is global warming potential, which is why attention has shifted from ozone protection to the HFC phase-down.
ODP still matters for old equipment. A second-hand cabinet or an old cold room still running on R22 will become harder to service as remaining supplies dwindle, and technicians may suggest a retrofit or replacement. Ask what refrigerant an older unit uses before taking it over with a shop or kitchen.