Is it possible for people to survive in air that is completely dry?

Human beings cannot survive without water. If you spend any amount of time in zero humidity, whether in an extremely hot desert, in an extremely cold artic region or in space, you would need protective clothing, which would keep your dehydration in check. You would also need an ample and constant supply of water or any other drinkable, non-poisonous liquid. For further information, go to your nearest library and read on the topic from a comprehensive book on biology.