Topic
- Precipitation (Meteorology) 264
- Commerce 216
- Aquifers 214
- Climate 211
- Sewage 191
- Population 182
- United Nations 165
- Saline water conversion 162
- Contamination of environment 158
- Resource allocation 156
- Water diversion 151
- Canals 149
- Economic development 146
- Political parties 142
- Negotiation 133
- Bibliography 111
- Health 111
- Pipelines 109
- Wells 104
- Reservoirs 94