30,000 people live on and around Calcutta’s landfill site at Dhapa.
"Inextinguishable fires burn all day and night, which pollute the air. They are so ubiquitous that the workers no longer complain about the fumes, and municipal authorities don’t bother to put them out.
Sovan Chatterjee, the mayor of Kolkata, says: “Of course there are fires. There are so many waste materials there; they are going to be bad for the environment.”
... “The fires come on their own, from the garbage itself because of biogas,” he says, referring to gasses produced as a result of fermentation of organic waste. “They burn all day and all night, every day of the year.”
...
At Dhapa thousands of plots of land are farmed for vegetables, the swamps have become fish farms and in the huts, women fry puchkas, a popular local street food. Though no one has ever measured how much of Kolkata’s food comes from the landfill site, it is an open secret that the city’s markets are stocked with produce from Dhapa."
https://www.theguardian.com/cities/2016/oct/24/difficult-breathe-inside-kolkata-india-rubbish-dump-permanently-fire