Russia has declared a state of emergency over wildfires in Krasnoyarsk Krai and the Irkutsk region with fumes engulfing an area larger than the European Union.
Nearly 3 million hectares are ablaze throughout mostly Siberia and parts of the Arctic, with the fire also spreading to the Far East, the Siberian Times reported.
The emergency also encompasses Krasnodar Krai and partially the Republic of Buryatia.
The fires are destroying permafrost north and south of the Arctic Circle as they burn through the tundra.
The Russian branch of the environmental group Greenpeace said the fires have "long ceased to be a local problem of the Siberian and Far Eastern regions" and they have "become an environmental disaster throughout the country."
The alert follows flooding in the Irkutsk region where more than 1,000 people were evacuated on July 29. Some 2,000 people were also evacuated in major flooding in Amur region of Russia's Far East.
More than 470 residential houses in 20 settlements have been affected by floods that restarted on July 27 after heavy rains hit the area.
Earlier reports said that part of the Siberian federal highway was temporarily closed due to flooding, TASS reported.
Twenty-five people have been killed, and seven have gone missing since the first wave of floods started in late June.
The Irkutsk regional town of Tulun has suffered the most damage, with 123 homes flooded in which 449 people lived, 65 of whom were children.