Environmental experts say levels of contamination were 193 times normal.
Locals warned not to use water for baths as authorities urgently check for radioactive or toxic substances.
Yet nickel capital Norilsk - the city with the highest industrial emissions - does not feature in the top ten.
Vet clinics inundated with cases of cats and dogs suffering health problems and rashes in 'Dirty 30' Siberian city.
Krasnoyarsk's skies have been black since the start of the New Year, with locals complaining of 'chemical smell', lack of oxygen.
Oil slicks, sewage, industrial waste and rubbish floating sea is harming wildlife and could lead to marine crisis.
Shocking pictures reveal colour of Daldykan River with locals claiming the waste from a nickel plant is to blame.
The Usolyekhimprom facility, disused due to bankruptcy in 2017, is a ‘toxic catastrophe waiting to happen’.