From Michael Specter’s article in the New Yorker (not online):
Nearly half the people in the world don’t have the kind of clean water and sanitation that were available two thousand years ago to the citizens of ancient Rome. More than a billion people lack access to drinking water, and at least that many have never seen a toilet. Half of the hospital beds on earth are occupied by people with an easily preventable waterborne disease. In the past decade, more children have died from diarrhea than people have been killed in all armed conflicts since the Second World War.
Clean water isn’t a technological problem, and it doesn’t require any fancy science. The reality is much simpler and sadder: dirty water is a problem of public policy. I have a vivid memory of walking in Calcutta, in a relatively nice part of town. I was returning from a large internet cafe, where I just written emails to friends and family half a world away. But as I walked back to the apartment – an apartment that only had clean water for a few hours a day, often late at night – I noticed the filthy open sewer running parallel to the street. Rats scampered back and forth. The stench was pervasive, almost like the hum of a noise in the background. This is the paradox of the modern world: that broadband can coexist with a lack of clean water. That our ability to transplant hearts can’t prevent millions of people from dying of diarrhea.