Officials say poisonous smog that contributed to higher death rates in Moscow has returned to Russia's capital.

Acrid smoke from forest and peat bog fires blanketed Moscow until early this week, nearly doubling the number of recorded deaths and grounding planes at airports.

Wildfires raged across central and western Russia. More than 50 people died in the wildfires and more than 2-thousand homes have been destroyed.

Alexey Popikow, Expert of Moscow Ecology Monitoring Agency, said, "During the day the concentration of indicators of smoke pollution will exceed the regular levels in the capital. In particular, the level of hydrocarbon emissions was 5.5 times higher then the usual Moscow level Sunday morning."

Emergency officials says the number of wildfires outside Moscow stood at 16 early Sunday.

This summer is the hottest since records began in Russia 130 years ago. Daily high temperatures reached up to 38 degrees Celsius, compared with the usual summer average of 24 degrees.

Scientists say the heatwave reflects the global climate's increased volatility.