Health threats
In addition to the problems faced by stargazers, the atlas also suggests that excessive light pollution can have biological consequences for wildlife and even human beings. Many scientists believe excessive use of artificial light can disrupt people's circadian rhythms - the "body clock" that determines when we eat, sleep and rise - and in doing so can raise the risk of a wide range of illnesses and conditions, from poor eyesight and bad skin to breast cancer.
Many governments fail to realize the importance of controlling the effects of light pollution, which should be treated as severely as air, water and soil pollution, according to Wang.
In many countries, when the light emitted by streetlamps, homes and illuminations is thrown up into the sky, it bounces off particles in the atmosphere and creates a phenomenon known as "sky glow", a diffuse glare that is a key factor in light pollution, which obscures many celestial bodies except for large, relatively close objects, such as the Moon.
Even astronomical observatories in or close to China's megacities are being affected by the excessive use of artificial lighting, according to Zhang Chao, a writer and editor at the National Journal of Chinese Astronomy.
"For example, a large observatory in the Changping district in Beijing, which was built in 1958 and which set China's standard time for many years, had to be decommissioned as a result of the worsening light pollution in the 1990s," he said.
Zhang explained that the observatory was affected by light pollution caused by the development of the nearby Huilongguan community, a large-scale residential neighborhood that houses more than 300,000 people.
He urged governments to take effective measures to tackle light pollution, and said measures should be introduced immediately, before more observatories and scientific research are affected.
