Urban & municipal planning 8 City & town planning - architectural aspects 6 Urban communities 5 Ecological science, the Biosphere 4 Environmentally-friendly architecture & design 4 Human geography 4 Agricultural science 3 Central government policies 3 History of medicine 3 Public health & preventive medicine 3 Sociology 3 Agriculture & farming 2 Applied ecology 2 Architecture 2 Conservation of the environment 2 Development economics & emerging economies 2 Environmental management 2 Environmental monitoring 2 Migration, immigration & emigration 2 Pollution & threats to the environment 2 Social & cultural anthropology, ethnography 2 Social impact of environmental issues 2 Social welfare & social services 2 Sociology & anthropology 2 Water supply & treatment 2 Age groups: children 1 Anthropology 1 Applied mathematics 1 Architectural structure & design 1 Architecture: professional practice 1