Water 228 Atomic and Nuclear physics 187 Water conservation 146 Water resources development 116 Water pollution 103 Water management 101 Irrigation 98 Water-supply 96 Physics 91 Water resources 78 WTO 74 Engineering 69 Aquatic ecology-- Fresh water ecology-- Pond ecology-- Limnology 66 Atoms 64 Chemistry 64 History 64 Water quality 61 Ecology 57 Economics 52 Hydrology 51 Pollution 50 Aquatic ecology-- Fresh water ecology-- Pond ecology-- Limnology (biology)-- groundwater ecology 49 Water treatment 47 Nuclear physics 46 Watershed management 44 Environment 43 India 43 Water quality management 43 Agriculture 41 Molecular spectroscopy; Nuclear structure; Atomic and Nuclear physics 41