Brasília: Smoke covers the sun during a fire at a national park close to the capital

 Smoke covers the sun during a fire at a national park close to the capital Brasília, Brazil

Thick smoke spews from the summit of Mount Sinabung as it erupts in Indonesia

Thick smoke spews from the summit of Mount Sinabung as it erupts in Indonesia

Thick smoke and ash spew from the summit of Mount Sinabung

Thick smoke and ash spew from the summit of Mount Sinabung, as seen from Tanah Karo in Sumatra

Smoke rises as firefighters rush to the scene after an explosion at a fireworks factory

Smoke rises as firefighters rush to the scene after an explosion at a fireworks factory in Yichun

Smoke caused by forest fires rises from the Peneda-Geres national park

Smoke caused by forest fires rises from the Peneda-Geres national park

A newly married couple shares a tender moment despite the deep layer of smog from wildfires

A newly married couple shares a tender moment despite the deep layer of smog from wildfires covering the ancient Russian city of Ryazan. 

People pass the monument of Marshal Zhukov

People pass the monument of Marshal Zhukov as heavy smog covers Moscow