Effective management of wastewater remains a persistent problem in East Asia, with discharge of untreated wastewater from domestic, industrial and agricultural sources a common occurrence. Across Asia, a majority of sewage still finds its way to rivers, lakes and coastal zones and oceans without any treatment. The impacts on freshwater, coastal and marine ecosystems and communities have been significant, including hypoxia, loss of fisheries productivity and biodiversity, and damage to human health.