Our series continues today with a look at technology. Charles Fishman, author of The Big Thirst, has seen plenty of water filters that fail and he talks about the "people factor." Physicist Ashok Gadgil grew up in India where several of his baby cousins died from bad drinking water. He came up with a kind of filter that's cheap and easy to repair, and he's hopeful about the success. It means millions of people now have clean water to drink.