A friend of mine lives in a middle-class neighborhood of New Delhi, one of the richest cities in India. Although the area gets a fair amount of rain every year, he wakes in the morning to the blare of a megaphone announcing that freshwater will be available only for the next hour. He rushes to fill the bathtub and other receptacles to last the day. New Delhi’s endemic shortfalls occur largely because water managers decided some years back to divert large amounts from upstream rivers and reservoirs to irrigate crops.