Five months into almost universal mask wearing in Hong Kong and it’s clear that the face coverings are not going away any time soon. We’ve adapted well – we’ve got a ready supply, the prices have dropped, and there are now plenty of fashionable alternatives to surgical masks – but there are still people who haven’t got the message about how to dispose of their mask safely.

Hiking trails, beaches and pavements are littered with used surgical masks. The offenders are worse than your standard…