Indian Water Crisis
Been studying this a while. India is projected to possibly be the first Nation in history to go completely dry in 10 years or so (many Cities are already at crisis levels). And it will be a problem there because India is the World's 2nd largest population (over a billion people).
This will also affect many other Country's. As water becomes more scarce, the intensity will increase, and we may actually see wars over water (dying of thirst, people will have nothing to lose really).
Sounds like science fiction, but this is real!
What is somewhat concerning is that India is a Nuclear Power, and, at some point, may use that!
Water may be the reason for World War 3!