Why was R-22 banned?

R-22 was banned because it is a hydrochlorofluorocarbon HCFC that damages the stratospheric ozone layer and contributes to climate change. R-22 contains chlorine, and when it leaks to atmosphere, it eventually reaches the stratosphere where ultraviolet radiation breaks it down, releasing chlorine atoms that catalytically destroy ozone molecules that protect Earth from harmful ultraviolet radiation, causing ozone hole and increasing skin cancer and environmental damage. Although R-22 has lower ozone depletion potential than CFCs like R-12, with ODP of 0.05 compared to 1.0 for R-12, it still depletes ozone and was targeted under Montreal Protocol of 1987 and its amendments for phase-out. Additionally, R-22 has high global warming potential of about 1810 over 100 years, contributing to climate change when leaked. Due to these environmental impacts, developed countries agreed to freeze production, then reduce quotas, and finally ban production and import of virgin R-22 from January 1, 2020, allowing only reclaimed R-22 for servicing existing equipment. The ban aims to protect ozone layer and reduce greenhouse gas emissions, encouraging transition to zero ODP, lower GWP alternatives like R-410A, R-32, and R-454B.