A deep layer of smog from wildfires around Moscow is hanging over the Russian capital, prompting many city residents to wear masks and forcing many planes to divert to other airports.
The thick haze is hanging over Moscow for the second straight day on Saturday as southeastern winds blow smoke from the areas worst affected by peat bog and forest fires.
Weather experts said that the winds are unlikely to change over the next few days.
The concentration of airborne pollutants such as carbon monoxide has further intensified and is at six times normal levels, according to city health officials the worst seen to date in Moscow.
Visibility is down to a few hundred meters, and about a dozen flights bound for Moscow's Domodedovo and Vnukovo airports were diverted to other airports.