Urban growth is increasing the demand for freshwater resources, yet surprisingly the water sources of the world’s large cities have never been globally assessed, hampering efforts to assess the distribution and causes of urban water stress. We conducted the first global survey of the large cities’ water sources, and show that previous global hydrologic models that ignored urban water infrastructure significantly overestimated urban water stress.

Delhi with fast-growing rate of urbanisation is the second most water-stressed cities in the world according to this new research published in Global Environmental Change Journal which has mapped 500 large cities to determine how global urbanisation is affecting water supplies. Kolkata (6), Chennai (18), Bangalore (19) and Hyderabad (20) are also listed in this first global survey of the large cities’ water sources.