Urban light pollution: Why we're all living with permanent 'mini jet-lag'

New York, the city that never sleeps, is brightly lit through the night. Doctors say light exposure at night can cause changes to our physiology. - AFP

Studies show that exposure to light after dusk is unnatural, and may be detrimental to health. Do we need 24/7 garages, supermarkets and TV – or should the city that never sleeps be put to bed?

Astronomer Dr Jason Pun of the Hong Kong University department of physics has been studying light pollution for nearly a decade. He says people often ask him if he’s crazy. “‘Hong Kong is supposed to be bright,’ they say. ‘Why are you even talking about light being some kind of pollution?’”