Black snow falling in Siberia due to air loaded with coal dust prompted the regional governor on Tuesday to temporarily close a coal processing plant he accused of killing residents.

Residents posted pictures on social media of cars and buildings under layers of black or greyish snow, with some saying it looked like Mordor, a terrifying blackened realm in Tolkien's "Lord of the Rings" saga.

"It depresses you when everything around you is black. And you understand it's extremely harmful for your health," said Natalya Zubkova, 42, editor of an online newspaper in one of the affected cities, Kiselyovsk.

"Our children aren't going outside to play at all," she said, with the black snow likely to remain on the ground till the end of April.

Laboratory tests found the level of air pollution was more than double safe limits, police said as they launched a probe into environmental pollution focusing on Kiselyovsk.

Prosecutors focused blame on the Cherkasovskaya coal processing plant in Kiselyovsk where they said they found "long-term, systematic" violations of air pollution limits, adding that this causes lung disease.

The plant does not filter coal dust in any way before releasing it into the atmosphere, prosecutors said.

Regional governor Sergei Tsivilyov on Tuesday upbraided the plant management for "killing" local residents and ordered a temporary shutdown.

"You are killing yourself and you are killing all your people who work for you and you are also killing everything around you," the governor said in televised comments.

"I'll hand all the documents on your plant to law enforcement authorities and I will oversee your plant personally," he added.

The region where the black snow fell is part of Russia's vast Kuzbass coal field, one of the largest in the world, which also has many highly-polluting metallurgical plants.

(This story has not been edited by Business Standard staff and is auto-generated from a syndicated feed.)