The amount and [brightness / brighten] of light from towns and cities around the world is at such a [height / high] level that it is reducing the darkness of night. Once upon [a / the] time, when night-time fell, we were [plunger / plunged] into darkness. Things are different, and brighter today. A study published [in / on] the journal Science Advances reports that [artificiality / artificial] light at night is increasing in most countries worldwide. Scientists say it [grew / grown] by 2.2 per cent a year between 2012 and 2016. The intrusion of artificial light into out night-time is causing [them / us] many problems. The International Dark-Sky Association says it, "is not only [imparting / impairing] our view of the universe, it is [adversely / adverse] affecting our environment, our safety, our energy consumption and our health".
Study co-author Franz Holker said artificial light is a [treat / threat] to our natural environment. He said: "Artificial light is an environmental [pollution / pollutant] that threatens [nocturnal / nocturne] animals and affects plants and microorganisms." He added: "[It] has [ecology / ecological] and evolutionary implications for many organisms from [bacterial / bacteria] to mammals, including us humans, and may reshape [entirety / entire] social ecological systems." Many environmentalists thought the [introduction / introductory] of LED lights would help the [planetary / planet] . However, cities are using more LED lights because they are [cheapened / cheaper] , which is adding to the light pollution. Night-time light decreased in 16 countries, including war-torn nations such [was / as] Yemen and Syria.