Why we are still monitoring the ozone hole

It’s almost 40 years since the first report of an ozone hole over Antarctica and 35 years since the Montreal Protocol to ban CFCs came into effect. In this week’s Our Changing World, Claire Concannon travels to Lauder in Central Otago to learn how the ozone hole forms, howe we measure it, and why, having solved the CFC problem, scientists are still monitoring it so closely.