The sounds of Al-Atash! Al-Atash! from young children in the camp of Imam Husain AS are narrated in the annals of Karbala. The enemy had blocked access to the River Euphrates since the 7th Muharram.
Ibn Ziyad sent a brief letter to Umar ibn Sa’d that commanded, “Prevent Husain and his followers from accessing water and do not allow them to drink a drop [of water]. Ibn Sa’ad followed the orders, and 5,000 horsemen blockaded the Euphrates. The water blockade continued up to the end of the battle on Muharram 10th (October 10, 680 AD)
Ibn Ziyad’s instructions to Umar Al-Sa’d was to cut off water supply to Imam Husain AS, but allow everyone else access. Second, lack of water would intensify the thirst of the men, women and children of Imam Husain AS’ camp. Besides, the men of Imam Husain’s army were toiling under the sun being wounded and bleeding. Thus, their thirst increased by the minute. Imam AS had to go the battlefield at each companion, and kinsmen’s side and that exertion, anxiety and sorrow must have made his thirst unbearable. That was the plan, to weaken the resolve of the Imam AS and his men by denying them water. Perhaps, they thought that the children’s anguished cries of Al-Atash would weaken the Imam AS’ resolve and that he would submit to the tyrannical Yazid’s demand. Yazidites had not reckoned that Imam Husain AS was the grandson of The Prophet SAWW who had refused to give up his mission despite all the threats, harassments and boycotts he faced from The Qureish. Third, the enemy feared that Imam Husain AS would use the waterways to seek reinforcement from Kufa. They did not want anyone to go or come over the River Euphrates to help Imam Husain AS. Fourth, the enemy wrongly thought that thirst would weaken the Imam AS’ brave men so much that they would not be able to put up a fight and hence very few men of Yazid would be lost and the battle won easily.