Gauteng: the hub of the South African economy. But at what cost? For years, its citizens have paid the price for the deadly fallout of its air pollution. From radioactive fallout to sulphur dioxide emissions carried in tiny dust particles, many Gauteng residents are falling ill under a toxic blanket of dirty air. In winter, some Gauteng cities rank amongst the top 20 most polluted in the world. What silent killers are hiding in the murky layers of its sky? Carte Blanche took a toxic tour around the province to find out.