Water, sanitation and hygiene: The unfinished agenda in the World Health Organization South-East Asia Region.

Access to adequate water, sanitation and hygiene (WASH) is essential for the health, well-being and dignity of all people. The World Health Organization South-East Asia Region has made considerable progress in WASH provision during the past two decades. However, compared with increases in coverage of improved drinking water, in some parts of the region, access to adequate sanitation remains low, with continued prevalence of open defecation. The Sustainable Development Goals (SDGs) have set ambitious targets for WASH services to be achieved by 2030. Examples of major health outcomes that would benefit from meeting these targets are diarrhoea and nutrition status. Although the total number of deaths attributable to diarrhoea declined substantially between 1990 and 2012, inadequate WASH still accounts for more than 1000 child deaths each day worldwide. And, despite the reductions in mortality, diarrhoea morbidity attributable to diarrhoea remains unchanged at around 1.7 billion cases per year. It has been known for decades that repeated episodes of diarrhoea increase a child's risk of long-term undernutrition, reduced growth and impaired cognitive development. Nutritional effects of inadequate WASH also include environmental enteropathy, leading to chronic intestinal inflammation, malnutrition and developmental deficits in young children. Inadequate WASH also contributes to iron deficiency anaemia resulting from infestation with soil-transmitted helminths. The cross-sectoral emphasis of the SDGs should act as a stimulus for intersectoral collaboration on research and interventions to reduce all inequities that result from inadequate WASH.