The map actually reflects “Annual Composite of Night-time Lights from 2003”. The NOAA website also carried the colour-composite version of the map.

“That image, based on data from the Operational Linescan System flown on US Defense Meteorological Satellite Program (DMSP) satellites, is a colour-composite created in 2003 by NOAA scientist Chris Elvidge to highlight population growth over time,” NASA’s Earth Observatory had stated.