Tashtgozari is one of the old rituals that Iranian people, mainly those from northwestern regions, perform before the start of the lunar month of Muharram.
In the ceremony, mourners carry tubs of water, symbolizing the water of the Euphrates River which was denied to Imam Hussein (AS) his family, and his companions.
According to narratives, when Al-Hurr ibn Yazid blocked the path of Imam Hussein (AS) near Karbala, Imam Hussein (AS) saw the fatigue and thirst in him and his army and ordered companions to pour water into tubs so that both soldiers and animals can drink, despite lack of water resources.