This research looked at how much water farming in Tehran uses and if it leads to water shortages. They used a tool called Water Footprint to measure water use by different crops from 2008 to 2015. The study found that growing pistachios, cotton, walnuts, almonds, and wheat in Tehran uses a lot of water. For example, producing 1 kilogram of pistachios needs 11.111 cubic meters of water, which is a lot. They also found that in 2015-2016, there was severe water stress in the region due to agriculture using so much water. So, the study suggests that Tehran needs to find ways to use less water in farming to avoid running out of water.