A Greenpeace study shows that the town of Kriel in Mpumalanga is the second-highest emitter of toxic sulphur dioxide in the world.
KRIEL - It's a place where the very air you breathe could be deadly.
Environmental groups and residents say government is violating their human rights.
The problem is sulphur dioxide and particulate matter. Both substances are harmful to humans.
Eskom is accused of not complying with emission limits, as prescribed by law.
"Our electricity comes from Mpumalanga's coal-fired power stations," said Greenpeace Africa's Melita Steele.
"That means there's an incredible amount of air pollution and an incredible amount of disease it has caused."
NGOs say government is violating their environmental rights and are now turning to the courts.