The light pollution map has two base layers (road and hybrid Bing maps), VIIRS/DMSP/World Atlas overlays and the user measurements overlay.
Direct annual comparisons are to be avoided as there are too many factors involved.
For more information view the help
Send comments about the map to Jurij Stare
THE SERVER IS UNDER A HEAVY LOAD DURING AUGUST 10-15TH, SO BE PATIENT IF THE MAP LOADS SLOW OR BACKGROUND MAP IS NOT LOADING AT ALL. THANK YOU FOR YOUR UNDERSTANDING.