In recent months, parts of the Middle East have been thrust into the center of an unfolding environmental emergency, one that could rival the region’s political and security crises in terms of its severity and long-term impact: the deepening water scarcity crisis. Nowhere is this danger more visible than in Iran, where the specter of a “day zero” scenario is no longer a distant hypothetical but a looming reality for Tehran’s more than 9 million residents.