S Africa coal belt among world's pollution hotspots: Greenpeace

South Africa's eastern Mpumalanga province has the most polluting cluster of coal-fired power stations in the world producing record levels of nitrogen dioxide, a report by environmental campaign group Greenpeace said Monday.

Mpumalanga, which borders Mozambique, is the hub of South Africa's coal industry and boasts 12 coal-fired plants that supply the grid with 32 gigawatts.

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.

The goverment did not immediately respond to a request for comment.

Coal burning and transport emissions are the principal sources of air pollution in the region.

Nitrogen oxides (NOx) - including NO2 - are estimated to cause many thousands of premature deaths worldwide every year.

According to the World Health Organization (WHO), the gases aggravate asthma and bronchitis symptoms and are linked to cardiovascular and respiratory disease.

The Greenpeace report said that state electricity utility Eskom has antiquated, highly polluting coal-fired power stations that are in a poor state of repair. "Eskom has been applying for postponements from complying with air quality legislation," Steele added.

Although South Africa adopted tough climate targets with the National Climate Change Response White Paper in 2011 and is a signatory to the Paris Climate Change agreement, implementation has been slow.

The study found that plumes of dangerous NO2 pollution also regularly cover nearby Johannesburg and Pretoria because of their close proximity and regular headwinds.

"We found that there are nearly 2,200 premature deaths (annually) that come from this air pollution. You are looking at respiratory problems... heart diseases (and) lung cancer - it's a very scary outline," it said.

Other pollution hotspots flagged in the report included coal-fired power plants in Germany and India, and a total of nine coal power and industrial hubs in China.

Cities including Santiago de Chile, London, Paris, Dubai and Tehran were found to have high transport-related emissions.