Riga (RIA Novosti) — A blanket of snow with black dust has covered the Latvian capital, Riga, a local paper said on its website.

According to the Telegraph website, the black snow fell on Sunday along a highway linking downtown Riga with the residential Bolderaja district in the city’s northwest.

Several square kilometers in the country’s capital are covered by a black snow blanket, the paper said. Coal facilities in the Riga port are believed to be the reason of the natural phenomenon.

Neither port officials, nor the country’s environment authorities has commented on the report.