Abstract. The stratospheric ozone layer has been the centre of scientific interest for many decades for its fundamental role in the protection of any form of biological life on Earth’s surface from damaging Sun’s ultraviolet radiation (UV). From the 1970s there was suggestion in the scientific literature that inert gaseous pollutants have the potential to deplete the stratospheric ozone layer.  A study in 1974 suggested that chlorine monoxide (ClO•) produced from dissociated Chlorofluorocarbons (CFCs) might deplete ozone. In 1985 researchers at the British Antarctic Survey discovered the ozone hole in Antarctica, and NASA’s satellite measuring the total column ozone from the Total Ozone Mapping Spectrometer (Limb Infrared Monitor of the Stratosphere, NIMBUS 7) confirmed the 1985 event. The news came as a surprise to many scientists and send worrying signs to environmental organizations and authorities. The discovery of the mechanisms by which the CFCs initiated ozone depletion was also very important that led to Prof. F. Sherwood Rowland, Mario J. Molina and Paul J. Crutzen who was a pioneer in stratospheric ozone research (Max Plank Institute of Chemistry, Germany) to share the 1995 Nobel Prize in Chemistry. In response to the dramatic discovery of the Antarctic ozone depletion the Montreal Protocol (15.9.1987) was a global agreement to protect the stratospheric ozone layer by phasing out the production and consumption of ozone-depleting substances CFCs. In 1989, 12 EU nations agreed to ban the production of all CFCs by the end of the century. Despite the initial doubts of CFCs contribution to the problem, the Montreal Protocol was the most successful environmental regulation and to date is the only UN treaty ever that has been ratified by every country on Earth 197 UN Member States. It phases down the consumption and production of the Ozone Depleting Substances (ODS) in a step-wise manner, with different timetables for developed and developing countries. The  2019 documents (WMO, UNEP, US NOAA, NASA and the European Commission) presented the advances in scientific understanding of ozone depletion and the gradual recovery in the last decades.TheNorthern Hemisphere (Arctic) mid-latitude total column ozone is expected to return to 1980 abundances in the 2030s. The Southern Hemisphere (Antarctic) mid-latitude ozone hole is expected to gradually close, with springtime total column ozone returning to 1980 values in the 2060s.