In pictures: Moscow's smoky shroud

Moscow lies enveloped in smoke from forest fires burning outside the city. As visibility was reduced to 100 metres, flights were suspended at city airports and workers donned masks inside and out.

The blanketed Kremlin towers: Environmental officials blamed calm weather for not dispersing particles (AP)

Carbon monoxide was at twice permissible levels and nitrogen oxides also exceeded safety limits (AP)

Residents covered their faces as they went out (AFP)

Pregnant women, children and people suffering from asthma and heart disease have been urged to stay at home (AP)

The Novodevichy monastery pictured at the end of July: smog has been a problem all summer

Even the sun was obscured by the thick morning smog (AP)