The population of Iran‘s capital city is facing evacuation as the threat posed by dwindling water supplies continues to mount. The Karaj Dam, which supplies Tehran’s 15 million residents with a quarter of their drinking water, is currently at just 8% capacity, with others in similarly dire straits, prompting officials to consider drastic measures. The Middle Eastern country has been contending with severe drought for six years due to low rainfall, with reservoir levels reaching especially critical levels in recent months.

Water rationing has already been imposed in some parts of the city, but the worsening trend is also forcing discussion of more drastic solutions. Professor Kaveh Madani, director of the United Nations‘ (UN) University Institute for Water, said Tehran only has “a few days or even weeks of water left”.

He told CBC: “Day Zero, as we call it in the water sector, is near. It’s a day that the taps would run dry.”

Iranian president Masoud Pezeshkian warned last month that if the city doesn’t see rain by late November, rationing would begin, with evacuation as the next step.

Tehran, and the wider country, has grown increasingly vulnerable to drought in recent decades because of factors including its water-intensive irrigation, subsidised water use, and mass migration into urban areas, overstretching resources.

But Iran’s energy minister Ali Abadi has also blamed the crisis on water leakage from Tehran’s 100-year-old water infrastructure and damage from the country’s 12-day conflict with Israel in June.

Tehran is not the only city to have faced a potential “Day Zero” crisis, with Mexico City, Sao Paulo and Cape Town among those caught in a similar bind, the latter just last year.

For Iran, though, the problem isn’t a new one, with president Pezeshkian warning of looming water shortages as far back as 2011. Professor Madani told Sky News: “These things were not created overnight.

“They’re the product of decades of bad management, lack of foresight, overreliance and false confidence in how much infrastructure and engineering projects can do in a country that is relatively water short.”