Hong Kong is one of the most densely populated  cities in the world, but with night skies around 1,000 times brighter than globally accepted levels, it gains a bad reputation for its light pollution. A study by Hong Kong University found that brightness levels in the southern Chinese city's popular shopping district of Tsim Sha Tsui were 1,200 times greater than the international dark sky standard. The crowded city of 7 million residents , full or residential high-rises, towering office blocks and neon  advertisements, has no laws to control outdoor lightning. The result is that light pollution is thought to be much worse than in other large cities, including London, Sydney, Tokyo and Shanghai. "In Hong Kong , you can't go anywhere outdoor in the evening without your eyes being blinded by this really disturbing outdoor lightning," the light pollution survey's head Jason Pum told AFP. "The fact that we have all this light in the sky means energy is wasted," he said, adding that too much artificial lightning also affects nightly wildlife. Research has suggested that light pollution can cause a number of harmful health effects in humans, including sleeplessness and headaches and can also interrupt body clocks and hormones . The university survey, the result of five million measurements taken from points across the city, was released just days before the start of the annual Earth Hour event, organized by the World Wildlife Fund. People around the world will be encouraged to turn off the lights for an hour on Saturday night to raise awareness of climate change. Last year, a number of Hong Kong's major buildings along Victoria Harbour went dark to mark Earth Hour. "Anyway, we should do our best to reduce the amount of lightning and adjust it for the benefit of the environment." If you walk out at night in Hong Kong, you can see all those things except   _  .
neon advertisements residential buildings a dark sky with twinkling stars high office blocks