Norilsk
On 29 May 2020 a fuel reservoir collapsed, flooding the nearby Ambarnaya River with 20,000 tonnes of diesel fuel. The reservoir was the property of the local mining company, a Nornickel subsidiary, NTEK. Russian president Vladimir Putin declared a state of emergency.  The fuel was a reserve used as a backup for the main gas supply to a power plant. The storage tank was built on permafrost. According to a statement by the company, the permafrost could possibly have melted and become unstable because of climate change. An area of 350 square kilometres (135 square miles) has been contaminated. It will be difficult to clean this because there are no roads and the river is too shallow for boats and barges. Oleg Mitvol estimates that the clean-up will cost about 100 billion rubles (1.5 billion US$) and take 5–10 years.