The emissions of the energy plants fed by the coal extraction sites that make the Middelburg area one of the most polluted sites in the world, can reach the entire urban area of Johannesburg. The mountain range around Rustenburg affects the wind flow, resulting in an accumulation of air pollution above the city. Furthermore, the wind takes particles from the tailings that cover neighbouring urban areas with layers of dust. The various health implications range from respiratory diseases to DNA code alterations (uranium). The prevalent wind direction (North-West) enforces the between the richer suburbs in the North and the poor townships down South.