Znečištění ovzduší ve městech dramaticky stoupá. Smog má na svědomí miliony životů
Blue sky is seen over a blanket of fog enveloping the skyline of Chicago, as photographed from an airplane window November 21, 2012. Unseasonably warm temperatures created a heavy fog along Chicago's Lake Michigan. The blue line is formed by the clouds and fog meeting the sky. REUTERS/Kevin Lamarque (UNITED STATES - Tags: SOCIETY CITYSPACE ENVIRONMENT) Published: Lis. 22, 2012, 1:12 dop.