World Health Organization 80 Nepal 65 prevention & control 57 standards 51 Series 46 Health aspects 45 Environmental health 44 Public Health 44 Environmental aspects 40 Water quality 39 Water Microbiology 38 Water Supply 38 Pollution 37 Gezondheid 36 Quality Control 36 Water 36 Water Pollution 36 Water quality management 36 Guidelines 30 Prevention 28 Environmental exposure 27 Children 26 World health 21 Kathmandu 17 methods 17 Child Health 16 World Health 16 Child 15 Risk assessment 15 Disease Control 14