Impact of water, sanitation and hygiene (WASH) on child stunting and wasting in India: A propensity score matching analysis from the National Family Health Survey

Stunting and wasting are major public health challenges in India, contributing to high child morbidity and mortality. Beyond inadequate nutrition, poor access to water, sanitation, and hygiene (WASH) is increasingly recognized as a key risk factor. This study assessed the association between household WASH access and undernutrition among children under five years. We analyzed data on 143,467 under-5 children from the National Family Health Survey (2019-21). Undernutrition was defined using WHO growth standards for stunting, wasting, and underweight. Household WASH access was defined as improved drinking water, improved sanitation, and a handwashing facility. Kernel-based propensity score matching (PSM) estimated the average treatment effect on the treated (ATT). Undernutrition was consistently higher among children without WASH access (stunting 37% vs. 31%; wasting 19% vs. 17%; underweight 30% vs. 24%). After PSM, WASH access was significantly associated with reduced prevalence of stunting (ATT = -0.009, <i>p</i> < 0.05) and underweight (ATT = -0.008, <i>p</i> < 0.05), but not wasting. The protective effects were stronger among urban, wealthier households and female children, with no significant associations in rural or poorest households. Improved WASH access is modestly associated with lower stunting and underweight, highlighting the importance of equity-focused interventions.