Light pollution is growing rapidly and in some places the number of stars visible to the naked eye in the night sky is being reduced by more than half in less than 20 years, according to a study released in the journal “Science”. The researchers said the increase in light pollution that they found was much larger than that measured by satellite observations of Earth at night. For the study of the change in global sky brightness from artificial light, the researchers used stellar observations from 2011 to 2022 submitted by more than 51,000 “citizen scientists” around the world, mostly in the United States and Europe. The change in the number of visible stars reported was equivalent to a 9.6 percent per year annual increase in sky brightness, averaged over the locations of the participants, the researchers said. Over an 18-year period, given such star brightness change, a location with 250 visible stars would see that number reduced to 100, according to Agence France Press (AFP). The study coincided with the replacement of many outdoor lights with light-emitting diodes (LEDs), but the researchers said the impact on skyglow from the transition is unclear, according to the researchers. They also said the visibility of stars is deteriorating rapidly, despite (or perhaps because of) the introduction of LEDs in outdoor lighting applications. Existing lighting policies are not preventing increases in skyglow, they confirmed.