Last update: August 19th, 2019 at 3:00 pm
This type of smog is often caused by temperature inversions. Normally, air cools as it rises in altitude, but during an inversion, a pocket of warm air sits on top of the cool air and traps pollutants from escaping.
This image was captured by the Visible Infrared Imaging Radiometer Suite (VIIRS) on board the Suomi NPP satellite.
Image Credit: NASA Earth Observatory