Out of Eden Walk: On foot across northern India

National Geographic Explorer Paul Salopek talks about his walk through northern India, where modern farming with high-yield seeds, fertilizers and pesticides, tractors and motorized well pumps have made India self-sufficient in food. But as he tells The World's host, Carolyn Beeler, it has come at a cost to the environment, to the country's water supplies and to some traditional ways of life.