Reading fog data from INSAT 3DR

INSAT-3DR satellite in a clean room, with its solar panel deployed, ahead of launch in August 2016. Credit: ISRO

At 7.57 am today, the India Meteorological Department's Twitter handle posted this lovely image of fog over North India on January 21, as captured by the INSAT 3DR satellite. However, it didn't bother explaining what the colours meant or how the satellite captured this information. So I dug a little. https://twitter.com/Indiametdept/status/1352080311102828546 At the bottom right…