Topic
- International regimes 21
- Armed Forces 20
- Palestinian Arabs 20
- Wells 20
- Sewage 19
- Canals 18
- Drinking water 18
- Economic development 18
- Hydrology 18
- Droughts 17
- Food 17
- Human settlements 17
- Labor 16
- Health 14
- Imports 14
- Pipelines 14
- Water diversion 14
- Drainage 13
- Wars 13
- Aswan High Dam (Egypt) 12