Saw this article on Reuters:
Researchers in the United States and Canada have located 39 unreported sources of major pollution using a new satellite-based method, the U.S. National Aeronautics and Space Administration said.
The unreported sources of toxic sulfur dioxide emissions are clusters of coal-burning power plants, smelters and oil and gas operations in the Middle East, Mexico and Russia that were found in an analysis of satellite data from 2005 to 2014, NASA said in a statement on Wednesday.
The analysis also found that the satellite-based estimates of the emissions were two or three times higher than those reported from known sources in those regions, NASA said.