Is this Peruvian city the most polluted on Earth?
Residents of Cerro de Pasco, a city high in the Andes, say the soil is harming their children.
Peru's government has declared a health state of emergency for the region on three separate occasions, but has not accepted that mining activity is to blame.
Doctors are advising affected residents not to return to the polluted city, but those who have spoken to the BBC say they have nowhere else to go.
Video by Grace Livingstone and Jasmin Souesi.