In this case, higher tariffs (which may also provide an incentive for more efficient water usage) are essential to generate the financial resources needed for the investment and ongoing operation of water services. This is particularly true of the underdeveloped wastewater services (ADB, 2014). Some of this pollution is caused by widespread and indiscriminate dumping of solid waste, but a greater source is discharges of untreated sewage from municipal water utilities (World Bank, 2014b).