The study is based on a century's worth of observational data drawn from 100 river basins across the world.
Links:
[1] http://admin.indiaenvironmentportal.org.in/news/human-water-use-greater-thought
[2] http://admin.indiaenvironmentportal.org.in/category/newspaper/bbc-uk
[3] http://admin.indiaenvironmentportal.org.in/category/thesaurus/water-supply
[4] http://admin.indiaenvironmentportal.org.in/category/thesaurus/water-demand
[5] http://admin.indiaenvironmentportal.org.in/category/thesaurus/water-resources
[6] http://admin.indiaenvironmentportal.org.in/category/thesaurus/surface-water
[7] http://admin.indiaenvironmentportal.org.in/category/thesaurus/irrigation
[8] http://admin.indiaenvironmentportal.org.in/category/thesaurus/groundwater