GENEVA - The Earth's protective ozone layer is healing and the ozone hole in 2024 was smaller than in recent years, a UN meteorological agency said in a report Tuesday.

The low level of ozone depletion observed in 2024 was partly due to naturally occurring atmospheric factors which drive year-to-year fluctuations. However, the long-term positive trend reflects the success of concerted international action, reported the Ozone Bulletin of the World Meteorological Organization.

The report, offering encouraging scientific news for both human and planetary health, was issued to mark World Ozone Day on Tuesday and the 40th anniversary of the Vienna Convention, which recognized stratospheric ozone depletion as a global problem and provided the framework for mobilizing international cooperation in ozone research, systematic observations and scientific assessments.

"Forty years ago, nations came together to take the first step in protecting the ozone layer -- guided by science, united in action," said United Nations Secretary-General Antonio Guterres.

"The Vienna Convention and its Montreal Protocol became a landmark of multilateral success. Today, the ozone layer is healing. This achievement reminds us that when nations heed the warnings of science, progress is possible," he said.

According to the report's investigation, to date, the Montreal Protocol has led to the phase-out of over 99 percent of the production and consumption of controlled ozone-depleting substances, which were used in refrigeration, air conditioning, firefighting foam and even hairspray. As a result, the ozone layer is now on track to recover to 1980s levels by the middle of this century, significantly reducing risks of skin cancer, cataracts, and ecosystem damage due to excessive UV exposure.