A resident of Krasnoayrsk poses on a hill with the city on the background. Picture: social media Krasnoyarsk

The locals here, four time zones east of Moscow, call it Black Sky, a combination of weather conditions and the spews from dozens plants in the industrial city of one million people on the Yenisei river. Residents are urged to remain indoors, not open windows, wash floors more often than usual, and clear their noses and throats, or leave town if they have the chance.

It was on 17 February that airvisual.com measured air quality in Krasnoyarsk as worse than anywhere in the world.

The pictures here show how the city looked on this gloomy day.

The AQI - air quality index - was at 226 compared with nearest rival Mumbai on 180. At the time it was the only Russian city in the top ten worst offenders.

Since then things have improved, but the acute pollution is far from unknown here.



The Black Sky emergency mode was imposed sin 14 February in an attempt to reduce the smog. Pictures: social media Krasnoyarsk

The city has a longstanding problem inherited from Soviet times even though it stands amid pristine Siberian nature with spectacular mountain views.

The smog pollution comprises tiny particles of soot, asphalt, tyres, sulphates, nitrates, as well as compounds of heavy metals, nitrogen oxide and dioxide from emissions of cars and power station, and sulphur dioxide.

A major aluminium works and coal-fired heating plants are blamed.

The high level of contamination has led to demands for cuts in emissions from local industrial companies by up to 20%, with locals asking to switch from coal to natural gas in fuelling the nearby power stations. In 2016, some 200 companies were held liable for air contamination, with total fines at 2 million roubles - or $31,500.



The day the world’s most polluted city was in Siberia. Pictures: social media Krasnoyarsk, AirVisual.com

Metals plant RUSAL Krasnoyarsk was run 2018 targeted by local officials over alleged air contamination.

The governor of Krasnoyarsk region Alexander Uss has called for 'a set of extra measures to improve the environmental situation in the city’.

The Black Sky emergency mode was imposed sin 14 February in an attempt to reduce the smog.