food production accounts for about per cent of global water withdrawal oecd but now that the world s population is more than per cent urban cities are drawing increasing shares from rural areas in what is now often a zerosum game when water shortages occur the city tends to be favoured over the countryside putting food and industrial crop production at higher risk as urbanization focused on the world s great coastal cities proceeds the breakup of the soviet union the advent of marketoriented economic transitions in china and vietnam and the shift in national economic policy in india toward more accommodation of international trade have added substantially to the transformation of asia from agrarian to industrial and even postindustrial economies