https://phys.org/news/2018-10-safrica-coal-belt-world-pollution.html

Satellite data produced by a European Space Agency satellite and analysed by Greenpeace between June 1 and August 31 showed Mpumalanga's nitrogen dioxide (NO2) emissions to be the highest in the world.

"The most up to date satellite imagery from June to August this year clearly shows that when you look at just one pollutant, which is nitrogen dioxide, Mpumalanga is the worst hotspot in the world," Melita Steele, senior climate and energy campaign manager for Greenpeace Africa, said in a statement.