The unending desert

After a nuclear apocalypse, the atmosphere absorbed almost all of the water on the planet, leaving the land extremely dry. The survivors, struggling to keep from dying of thirst, become nomadic, fighting for supplies, and searching for the small, undeveloped settlements, but most survivors have a common enemy, the sweepers, bandits that seek and destroy those villages, ransacking and pillaging everything they could find, before they leave they burn it down, sending up a cloud of smoke that can be seen from miles around, a death sentience for anyone who sees it.