Why should places like Nairobi be short of water?

In Africa an estimated 160 million people live with water scarcity. Either because there isn’t enough water or it isn’t safe to consume. And the problem is worst in big urban areas. For places like Nairobi the problem is getting bigger with more people settling in the city. It's particularly bad in some areas, places like Dandora Phase 4 in the suburbs. Caroline Achieng used to sell tea there but the water shortages have forced her out of her trade. “If you wanted water, you would have to wake up at one am and fetch it.” She said “right now there is no water in the taps”. City authorities have blamed what have been described as water cartels for the problem. Those, who either hoard or sell water for profit. But is it really as simple as that? Professor George Okoye at Nairobi University says the city is “nineteen years late” with its infrastructure investment. In today’s Africa Daily Alan Kasujja looks at why cities like Nairobi are short of water