On 15 April 2012, safety walls of Mianrood River broke due to heavy rain in Tehran, and consequently, 300,000 cubic meters of water entered metro tunnel of Line 4. The two nearest stations were still under construction, so Metro operators had enough time to evacuate other stations from passengers. Nobody was killed, but water depth in the Habib-o-llah station, the deepest station on Line 4, was estimated to be near 18 meters. It took nearly two weeks to reopen the flooded stations which were previously in operation.