https://motherboard.vice.com/en_us/article/ev3g94/ozone-recovery-continues-but-suspected-emissions-from-china-slows-progress

When countries work together to confront global environmental problems, it actually works. That’s the upshot of the 2018 Scientific Assessment of Ozone Depletion, which found that Earth’s ozone layer has started to recover since humans got serious about preserving it more than 30 years ago.

The Montreal Protocol of 1987 enforced bans and regulations intended to phase out pollutants that break down ozone. Fortunately, those actions decreased harmful materials in the ozone layer and are enabling it to slowly bounce back.