Mexico City, Mexico—Situated in one of the world’s largest cities, the Bordo Poniente landfill site in Mexico City is set to close next year, as authorities fear contaminating the city’s natural water supply and possible flooding

The site is thought to be the world’s largest, taking in 11,430 tonnes of landfill every single day. According to a statement from the country’s Interior Ministry, pollution from the site represents a significant risk to the aquifer, the layer of water-bearing permeable rock from which water can be extracted.

The Ministry also cited a threat of flooding, as the masses of waste interfere with the operation of storm drains.

The statement described the closure as an “excellent opportunity for Mexico City to join global efforts to help reduce and control emissions of greenhouse gases and thus to mitigate climate change”. The site emits almost 1.4m tonnes of methane every year, according to the Clinton Foundation.

However, it failed to go into in any depth any replacement for the site, suggesting only that waste treatment centres “without harmful effects on the environment and the population” would be in operation from early 2012.

The site was established in 1985 and in the 25 years since has amassed 70m tonnes of waste.