Snow in the Siberian city of Achinsk has turned into a muddy gray that many suspect was caused by pollution from a nearby aluminum oxide factory, local media reported Monday.Photos and videos shared online show snowdrifts throughout the city, with a population of 100,000 people, covered in a thick layer of gray dust.“Some kind of powder is falling on people's heads, and this is considered normal environmental conditions?” a local man asks in a video shared on the Russian social media website VKontakte. “We can't recall anything like this.

Now one doesn't even need to take [air] samples to the laboratory — one can just collect them with a shovel, as the entire city is covered with this filth!" another person said.Dozens of residents have reportedly filed complaints with the authorities, prompting the Krasnoyarsk region's Environmental Ministry to launch inspections of the city's biggest industrial polluters.An aluminum oxide refinery and a subsidiary of Russian aluminum giant Rusal, which many blame for the gray snow, said that the plant has partially suspended its operations, local media reported. Authorities on Friday issued a “black sky” warning for several localities in the Krasnoyarsk region — which is over 3,000 kilometers east of Moscow — including Achinsk and the regional capital. The alert requires industrial facilities to temporarily reduce emissions during “unfavorable” weather conditions that impede the dispersion of pollutants into the atmosphere.The Krasnoyarsk region is regularly plagued by air pollution problems, with authorities in the capital city of Krasnoyarsk regularly issuing a “black sky” warnings due to heavy pollution.