"Water" here refers to the fresh water resources that people can drink and water flowers and fields. Sea water is salty, so people can't drink it directly, nor can it be used to irrigate fields and plant. They must be diluted. However, the cost of converting seawater into fresh water is high and it cannot be popularized. Most of the Middle East is desert and Gobi, with hot climate, scarce precipitation and few rivers, which makes the fresh water resources there very scarce.