1 / 4   A thick layer of white foam is seen covering the surface of Yamuna River in New Delhi, India, ahead of World Water Day. /CFP Photo

2 / 4   It may look beautiful, but the bubbles are actually toxic and malodorous, caused by industrial waste that has leaked into the river. /CFP Photo

3 / 4   Even though the river is one of the most polluted in India, thousands of devotees still bathe and worship there every year during festivals. /CFP Photo

4 / 4   Launched by the United Nations, World Water Day reminds the public of the importance of water on March 22 every year. This year, the theme is “Nature for Water,” which aims to find “nature-based solutions to the water challenges we face today.” /CFP Photo