More than 2.7 billion people will face severe shortages of fresh water by 2025. There is, __16__, only a limited amount of water on the planet. Less than 3 percent of the world’s water is fresh, and most of __17__ is trapped in polar ice or buried underground in springs too deep to reach. Freshwater lakes, rivers and reservoirs may seem __18__ but provide just a drop in the bucket. Even __19__ supplies are sufficient or plentiful, they are increasingly at risk due to various forms of pollution. Fierce national competition __20__ water resources has prompted fears that water issues contain the seeds of violent conflict. International cooperation is therefore by all means urgent.
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