Changes in ‘truly dark’ spaces in the EU-27 between 2014-2015 and 2020-2021

VIIRS - Visible Infrared Imaging Radiometer Suite. The Northern region has been excluded from the map due to the confounding effects of Aurora lights as detailed in Widmer et al. (2022). The value of 0.5 nW/cm²/sr was chosen as the threshold as it reflects the natural luminance of the night sky with a margin for uncertainties.