Mexico is one of the most light-polluted countries in the world

Light pollution, also known as photopollution or luminous pollution, is excessive, misdirected or obtrusive artificial light.

Mexico City, Ecatepec, Guadalajara, Puebla, Monterrey, Tijuana and Ciudad Juárez are the cities with the highest levels of light pollution in Mexico, said researcher Héctor Solano Lamphar.

In an interview, the expert in light pollution said that these cities have levels similar to Hong Kong, Madrid and Barcelona, which are considered the most light-polluted cities in the world.

Now, speaking in magnitude/sq. arcsecond, the unit used to measure the levels of light pollution, Mexico City has an average level of 16 magnitude/sq. arcsecond, while Ecatepec, Guadalajara, Puebla, Monterrey, Tijuana and Ciudad Juárez have levels between 17 and 18 magnitude/sq. arcsecond, according to the study carried out by Solano.

"To have a clearer idea of what this means, the magnitude per square arcsecond is a logarithmic scale used in astronomy to measure the brightness of stellar objects. Speaking of light pollution, the lower the level, the higher the pollution. 22 magnitude/sq. arcsecond is the degree of natural night sky. Therefore, these Mexican cities experience a very high level of pollution." the researcher said.

The 16 magnitude/sq. Arcsecond level registered in Mexico City is the same in Hong Kong, long time considered as the most light-polluted city worldwide.

While the Mexican cities with levels between 17 and 18 magnitude/sq. arcsecond can be compared with the average levels recorded in Madrid and Barcelona, which are cities with even more population and territorial extension than Mexican cities (except for Mexico City). 

As a major side-effect of urbanization, light pollution is blamed for compromising health, disrupting ecosystems and spoiling aesthetic environments.