A weary girl carries water for her family in a refugee camp outside Nyala, North Darfur, Sudan, during the summer of 2005. Some 2.7 million people were displaced by the conflict in Darfur, which appeared to be easing toward a close in early 2010. Refugee camps lack basic infrastructure, and residents must spend much of their time on survival tasks like finding clean water.
United Nations officials say each person on Earth requires 5 to 13 gallons (20 to 50 liters) of clean water a day for drinking, cooking, and keeping themselves clean. Refugees must make do with far less, and are often dependent on aid groups or governments to deliver water by truck.