environment protection environment 64 environmental pollution 63 permanently sustainable development 52 ecology 51 air pollution 42 waste disposal services 37 more ... wastes 36 recycling of wastes 30 unconventional energy sources 23 water courses 23 environmental management 22 ecosystems 17 environmental law 16 atmosphere (biology) 15 power engineering 14 water pollution 14 environmental policy 13 water management 13 health harmful substances 13 contaminants 13 coolants 12 issues 12 Earth warming 12 biofuels 11 sewerage 11 climatic changes 11 air cleanness monitoring 11 landscape recultivation 11 construction materials 11 less ...