Every year, the UN campaigns to raise awareness about environmental issues like marine pollution ... the most beautiful — and heartbreaking — images of our planet and its flora and fauna.

International open-water swimmer Meenakshi Pahuja recently swam from Revas Jetty in Alibaug to the Gateway of India to raise awareness on water pollution.

Many of the photos were taken before water and air pollution were fully regulated. The Clean Air Act was passed in 1970, and the Clean Water Act was passed in 1972. Baltimore, Birmingham ...