Related by context. Frequent words. (Click for all words.) 61 drip irrigation 59 irrigation 58 rainwater 54 flush toilets 53 conservation 51 solar panels 50 solar thermal 50 cisterns 50 geothermal heating 49 drought resistant 49 composting 49 afforestation 48 potable water 47 solar photovoltaic 47 cistern 47 organic farming 47 photovoltaic panels 47 reverse osmosis 47 drainage 47 stormwater 46 irrigate 46 irrigating 46 installing solar panels 45 desalination 45 planting trees 45 recycling 45 water 45 solar powered 45 solar 45 groundwater 45 solar PV 45 sprinklers 44 tree planting 44 potable 44 install solar panels 44 eco friendly 44 stormwater runoff 44 biogas 44 renewable energy 44 photovoltaic 44 rooftop solar 43 environmentally sustainable 43 catchment 43 carbon sequestration 43 photovoltaic PV 43 sprinkler systems 43 septic tank 43 sewerage 43 irrigated 42 rural electrification 42 septic tanks 42 Irrigation 42 conserving 42 geothermal 42 Solar panels 42 retrofitting 42 septic systems 41 effluent 41 organic gardening 41 landscaping 41 compost 41 greening 41 bio diversity 41 latrines 41 water heaters 41 environmentally friendly 41 gardens 41 desalination plants 41 reforestation 41 sustainability 41 plumbing fixtures 40 environmental sustainability 40 chlorination 40 photovoltaic cells 40 photovoltaic solar 40 watering 40 soil erosion 40 recycled materials 40 drought tolerant 40 sewage 39 soil fertility 39 wetland 39 septic 39 ecologically friendly 39 sustainable 39 cloud seeding 39 sanitation 39 vegetable gardens 39 waste disposal 39 water purification 39 toilets 39 wastewater treatment 39 greenery 39 eco 39 Drainage 39 recyclable materials 39 hydropower 39 reservoirs 38 Water Conservation 38 sewage treatment 38 catchment areas