The phenomenon increased at an annual rate of 9.6% between 2011 and 2022.
Every week during the spring, when the sun sets, 30 students from the Astronomy class at the University of Puerto Rico (UPR) in Cayey cross the campus carrying their telescopes and notebooks. They come to study the orbit of the planets and the properties of celestial bodies, but, increasingly, light pollution obstructs their view of the night sky.