HONG KONG - NOVEMBER 01: Advertising signs are lit at boutique store after opening hours at Central on November 1, 2016 in Hong Kong. Hong Kong is believed to be the most light polluted city in the world with local studies showing that levels in certain areas to be as much as 1,000 times brighter than international norms. Researchers have said the light pollution is thought to be much worse than in other major cities, such as London, Frankfurt, Sydney and Shanghai, as the city filled with high-rise buildings, office blocks and neon advertisements, has no laws to control external lighting. With a population of over seven million people, studies also suggested that the light pollution could also cause adverse health effects for humans, such as insomnia and headaches, and can also disrupt body clocks and hormones. However with light pollution studies still in the early stages and without strict international standards on quantifying the extent of light pollution, there hasn't been an accurate claim to the position. Other candidates include Las Vegas, Tokyo, Seoul, and New York, cited by those with the best view, astronauts. (Photo by Lam Yik Fei/Getty Images)
