Introduction Water, sanitation and hygiene (WASH) are recognised as critical determinants of health. Unsafe water, inadequate sanitation and poor hygiene are responsible for millions of preventable illnesses and deaths every year. By breaking the cycle of infection and reducing exposure to pathogens, WASH acts as the foundation for disease prevention and improved well-being. WASH and disease transmission Many communicable diseases are spread through the faecal-oral route. Human excreta, if not safely managed, contaminate water, soil, food and hands. Pathogens then re-enter the human body through drinking, eating or direct contact. Safe sanitation and hygiene practices block this pathway. Waterborne Diseases Contaminated drinking water transmits diarrhoea, cholera, typhoid and dysentery. Ensuring safe water through treatment, protected sources and clean distribution reduces incidence. (Source: WHO – Water, Sanitation and Hygiene). Sanitation-Related Diseases Poor sanitation leads to spread of soil-transmitted helminths (intestinal worms). Open defecation and poor waste management contaminate living environments. Hygiene-Related Diseases Lack of handwashing with soap allows germs to spread through food and person-to-person contact. Infections such as influenza, diarrhoea and eye diseases like trachoma are prevented through good hygiene. Neglected Tropical Diseases (NTDs) Schistosomiasis spreads through contact with unsafe water. Trachoma is linked to poor facial hygiene. WHO identifies WASH improvement as a key intervention for controlling several NTDs. Impact on child health and nutrition Diarrhoeal disease is one of the leading causes of death among children under five. Frequent illness reduces nutrient absorption, contributing to undernutrition and stunting. Safe WASH is thus not only a health intervention but also a nutrition intervention. (Source: UNICEF – Water, Sanitation and Hygiene for Every Child). WASH in health care facilities Availability of safe water, toilets and handwashing stations in hospitals and clinics is essential for infection prevention. Absence of WASH in delivery rooms increases risk of sepsis in mothers and newborns. WHO reports that one in four healthcare facilities globally lacks basic water services. Evidence and statistics According to WHO (2023), 1.4 million deaths annually are linked to unsafe WASH services. At least 1.7 billion people worldwide still lack basic sanitation, and 2 billion drink water contaminated with faeces. In India, government programmes such as the Swachh Bharat Mission and Jal Jeevan Mission have significantly expanded access, contributing to reductions in open defecation and diarrhoeal disease burden. Interventions for disease prevention Safe Drinking Water: Filtration, disinfection, household water treatment and safe storage. Sanitation Facilities: Household toilets, sewerage systems, proper faecal sludge management. Hygiene Promotion: Handwashing with soap at critical times, menstrual hygiene management, safe food handling. Institutional WASH: Ensuring services in schools, health centres and workplaces. Community Behaviour Change: Public awareness campaigns, participatory approaches such as Community-Led Total Sanitation (CLTS). Challenges Sustaining behaviour change in hygiene practices. Ensuring water quality monitoring and regular testing. Operation and maintenance of toilets and water supply systems. Addressing disparities between rural and urban populations, and among marginalised groups. Coping with climate change impacts such as floods and droughts that affect WASH systems. Example: The transformation of the village of Laxmipur In the village of Laxmipur, diarrhea was a constant problem. Nearly every month, children would fall sick, and the local clinic was overwhelmed. The village had a water source, but it was an unprotected pond where cattle also drank. Sanitation was poor, with open defecation leading to human waste being washed into the pond during monsoons. A local health worker, Geeta, recognized the link. She rallied the community to build household toilets and taught them about the "faecal-oral route" of disease. She explained that germs from open defecation were contaminating their pond water and hands. Geeta led a campaign to purify the pond water and provided families with simple water filters. She demonstrated how to properly wash hands with soap, especially before eating and after using the toilet. Within six months, the clinic saw a 70% reduction in diarrhea cases. This wasn't a miracle; it was the direct result of breaking the chain of infection through safe water, proper sanitation, and good hygiene. Conclusion WASH is among the most effective interventions for disease prevention. Safe water supply, improved sanitation and regular hygiene practices can drastically reduce child mortality, control epidemics and improve overall community health. Strengthening WASH systems in households, schools and health facilities is essential for achieving public health goals and the Sustainable Development Agenda.