Bow River Iron Bridge and Mount Lawrence Grassi on a hazy summer evening caused by wildlife smoke, Canmore, Alberta, Canadian Rockies, Canada, North America

Exhaust emissions, plume of smoke, chimney of a power plant, Kiel, Schleswig-Holstein, Germany, Europe

STEAG Evonik Walsum coal-fired power plant, Duisburg, Ruhr Area, North Rhine-Westphalia, Germany, Europe

One of four new blast furnaces which produce 11.5 million tonnes of pig iron annually, ThyssenKrupp Steelworks, Duisburg, North Rhine-Westphalia, Germany, Europe

Factory smoke stack, pollution

Factory smoke stack, pollution

Football fans on tribune lighting fireworks

Fog, smoke, in a forest, sun struggling to shine through the haze

High voltage power lines, wind turbine, Halde Scholven, mine heap, next to the Scholven coal-fired power plant operated by E.ON, Gelsenkirchen, North Rhine-Westphalia, Germany, Europe

Industrial chimney, backlight

Coal-fired power plant, Kiel, Schleswig-Holstein, Germany, Europe

Football fans on tribune lighting fireworks

Factory smoke stack, pollution

Coal-fired power plant, Kiel, Schleswig-Holstein, Germany, Europe

High voltage power lines on Halde Scholven, mine heap, next to the Scholven coal-fired power plant operated by E.ON, Gelsenkirchen, North Rhine-Westphalia, Germany, Europe