Iran is teetering on the edge of a catastrophic national water shortage, with its major cities facing the imminent threat of 'Day Zero' – the point at which urban water supply systems completely collapse. This environmental and political crisis is now fuelling widespread public unrest, presenting a profound challenge to the 47-year-old Islamic Republic.
A Nation Parched: The Imminent Threat of 'Day Zero'
Gripped by a severe drought now in its sixth consecutive year, Iran's meteorological organisation has issued stark warnings. The concept of 'Day Zero', previously experienced by Chennai, India in 2019, now looms over major Iranian population centres including Mashhad, Tabriz, and the capital, Tehran. By early December, taps in southern districts of Tehran had already run dry.
Nightly 'pressure cuts', where water supply is halted to entire districts of the capital, have become routine. This dire situation sparked summer protests where citizens chanted "Water, electricity, life – our basic right", often facing severe government crackdowns. The crisis reached a chilling apex in November when President Masoud Pezeshkian warned that if rains did not come, the city of 10 million people might need to be evacuated.
Roots of the Crisis: Climate Breakdown and Decades of Mismanagement
The evidence points to climate breakdown as a primary driver. Research cited by Middle East expert Juan Cole indicates that between 1990 and 2022, average temperatures in Iranian cities rose roughly twice as fast as the global rate. This impact has been catastrophically amplified by decades of water resource mismanagement spanning successive governments.
In pursuit of modernisation, both the former Shah's regime and the current Islamic Republic oversaw the abandonment of Iran's ancient qanat aquifer system – a 2,500-year-old network of approximately 70,000 tunnels that sustainably supplied water for millennia. Instead, Iran became one of the world's top three dam builders in the latter 20th century.
This strategy backfired. Dams were often built on rivers too small to sustain them, leading to increased evaporation and depriving upland areas. Post-revolution, a push for self-sufficiency led to the rampant installation of over one million groundwater pumps, 90% for agriculture, which have pumped ancient aquifers dry and caused severe land subsidence in cities like Isfahan.
International Tensions and a Breaking Point
The crisis has a critical international dimension, exacerbating regional tensions. Afghanistan's Taliban regime recently completed the Pashdan Dam on the Harirud River, controlling 80% of its flow into eastern Iran and threatening water supplies to Mashhad. Armed clashes over the Helmand River occurred in summer 2023, and with no formal treaty governing the Harirud, rhetoric is escalating.
Domestically, water scarcity compounds other severe pressures. Soaring inflation, exacerbated by a dramatic currency crisis and costly sanctions, has made daily life unbearable for many. The government's attempt to reform a corrupt preferential exchange rate system for imports in early December threatened to push food inflation, already at 72%, even higher.
When the biggest protests in years erupted, the fundamental insecurity induced by water shortage was a crucial, under-reported background. While sparked by immediate economic shocks, the upheaval represents a final break after decades of cumulative failure. In a world without climate breakdown, Iran's water mismanagement might have been less severe. Coupled with sanctions, it has tipped the system into a potential terminal crisis.
Iran's plight is a stark warning. A 2025 study from Pusan National University forecasts that a third of the world's most drought-prone regions could face 'Day Zero' before 2030. The failure of Iran's water supplies is a dramatic example of how the climate crisis directly threatens essential human needs and, with them, political stability. It is unlikely to be the last.
