Shanghai, known as the “city with no night” because of its extravagant electric signs, is about to dim the lights in an effort to crack down on light pollution. The chief of lights and advertisements for the city’s environmental bureau said the bright lights make it hard for residents to sleep, wash out the night sky and harm the environment. Bright lights have been Shanghai’s hallmark for years and it is hard to imagine the business community going along with the plan, but it may be driven by electricity shortages that have caused power rationing to shopping malls and factories since the fall. More restrictions are expected this summer.