Light pollution
Light pollution is the excess of artificial light that illuminates the exterior and interior of our towns and cities at night.
One of the big problems lies in the change of light bulbs that is being carried out, traditional light bulbs are being replaced by LED bulbs due to their greater energy efficiency, but the change in the amount of light they produce is not being taken into account. We find a rebound effect, energy expenditure is lower, but light pollution skyrockets.
Spain is the third country in the European Union where there is more light pollution and where there is greater spending on public lighting per inhabitant. Madrid is the city that emits the most power and, therefore, throws the most light into the sky, followed by Zaragoza, Seville, Barcelona and Valencia. However, if we look at the cities with the most polluting lighting, the ranking is headed by Bilbao, followed by Hospitalet de Llobregat (Barcelona) and Barakaldo (Bizkaia).
From the Earth at Night website you can see a map of light pollution in the world.