Air pollution is a global environmental health problem, especially for those living in urban areas. Not only does it negatively impact our ecosystems, it considerably affects our health. According to the World Health Organization (WHO), around 8 million premature deaths per year are linked to air pollution, more than double of previous estimates.

How glaciers turn lakes turquoise

Four large lakes on New Zealand's South Island stand out for their distinctive turquoise colour. Water rich with glacial flour can be seen flowing from the Godley River into the north end of Lake Tekapo. The Operational Land Imager on Landsat 8 acquired these image on 1 and 12 May 2019.