Water: Mumbai ranks average in water. The city’s score is helped by a fairly efficient water system, losing just 14% of its water flow through leaks versus the Index average of 22%. This is the second best rate among cities with similarly low incomes in the Index (under US$10,000 in per capita GDP). The city has benefited from recent official efforts to reduce water leakages, which once ran as high as 50%. Mumbai is also comparatively sparing in its water use, consuming on average 250 litres per capita per day versus the Index average of 278 litres. In addition, Mumbai’s sources its water supply from lakes and rivers rather than less sustainable sources, such as deep aquifers and desalination plants. To combat periodic water shortages, however, Mumbai has undertaken feasibility studies to build a number of desalination plants.