"Because even though his army was outnumbered, he cleverly calculated his advantages. The enemy was downwind and there was a drought. Their defenses burned to a crisp in minutes."
— Azula explaining how Fire LordSozin won the battle.
The city of Han Tui was besieged by Fire Lord Sozin's army. Despite his forces being outnumbered, Sozin carefully calculated his advantages; a prolonged drought had both limited the supplies of the defenders and created ideal conditions for a wildfire, and Han Tui's position downwind of the Fire Nation Army meant that the flames would spread toward the city. With the defenses completely obliterated in minutes, Sozin's forces converged on the city and won the battle.
The Battle of Han Tui bears resemblance to the Battle of the Red Cliffs, during the Three Kingdoms period, when warlord Sun Quan scored a decisive victory against Cao Cao's fleet. He attacked using fire against the enemy, which was in the opposite direction of the wind.