Average population exposure to light pollution — share living under a night sky brighter than 1% of natural (2015)

This statistic estimates the percentage of each country’s population living under night skies where artificial skyglow makes the sky at least 1% brighter than its natural background level. It is a widely used threshold for “light-polluted” skies because it marks a level where human-caused sky brightness becomes detectable and begins to degrade visibility of faint stars.

The underlying global model comes from the World Atlas of Artificial Night Sky Brightness (2015), which combines satellite measurements of upward radiance with atmospheric scattering modelling and terrain/altitude adjustments. Population exposure is then computed by overlaying the modeled sky brightness map with gridded population counts and aggregating results to the national level. This offers a globally comparable view of how much of each country’s population experiences degraded night skies due to outdoor lighting.