Kabwe, Zambia, has a long history of lead and zinc mining, centered around the now-closed Broken Hill Mine. Due to the mine, the city is also one of the most polluted places on Earth; even though the mine has closed, artisanal/small-scale mining continues, leading to the expansion of the polluted area.
Click here for original story, The lasting effects of pollution from the Kabwe mine
Source: Phys.org