English: Average length x the dryness of droughts from 1901 to 2008. Source: World Resources Institute
Map made by Sampa, with material downloaded from Aqueduct, World Resources Institute. "The World Resources Institute is committed to transparency and open data. The data and methodology behind Aqueduct are documented and available for download. All the products, methodologies, and datasets that make up Aqueduct are available for free use under the Creative Commons CC:BY license."