Why in News?

•       A study by the World Wildlife Fund (WWF) evaluated 400 cities globally in 2018 with focus on megacities facing high combined levels of water scarcity — recent and projected drought.
• Highlights:
•       Four Indian cities, Chennai, Kolkata, Mumbai and Delhi have been ranked among the top 20 megacities in the world facing high levels of water scarcity.
•       Chennai has emerged in top position as the city facing the most severe water scarcity and drought in the world.
•       Kolkata has been ranked at number 2, Mumbai at 11 and Delhi at 15.
•       Large cities, mostly located along the banks of large rivers, are vulnerable to water scarcity because of the vastly over-allocated and mismanaged river-systems.
•       Frequent droughts and flooding due to climate change and depleting levels of water in the reservoirs are some of the reasons behind the water crisis in these megacities.
•       Reports have noted that the world has lost 35% of its wetlands since 1970 and is losing them three times faster than forests.

World Wildlife Fund (WWF):

•       The WWF was founded in September, 1961, at the International Union for the Conservation of Nature and Natural Resources (IUCN)’s headquarters in Morges, Switzerland.
•       As an international fundraising organization, it is working in collaboration with existing conservation groups and bring substantial financial support to the conservation movement on a worldwide scale.