Sleepless in Hong Kong.

Study finds Hong Kong is the most light polluted city on Earth. CNN's Andrew Stevens reports.

CNN's Andrew Stevens reports that Hong Kong has more light pollution than any other city on the planet, and that's causing its citizens to lose sleep. According to University of Hong Kong researchers, who spent two years measuring it, Hong Kong gets 1,200 times more light than a dark night with no manmade light pollution. That compares to a typical European city, like Madrid, which registers only 100 on the light pollution scale. Unlike major cities like Shanghai, London or Sydney, where laws regulate the amount of lighting, Hong Kong doesn't have any laws, only guidelines, Stevens says.