Explanation:

ltutmish was the third ruler of the Mamluk dynasty of Delhi of Turkic origin. He constituted a corp of 40 loyal slaves Amirs Known as Turkan-i-Chihalgani. A select body of Turkish nobility originally slaves of Iltumish which came into existence during the period of Iltumish to be destroyed by Balban later .
The Forty a select body of Turkish nobles was created by Iltutmish for better and effective administration. The members of this body were chosen on the basis of loyalty and meritorious service. But after Iltutmish, the members of the Forty enjoyed unlimited power due to his weak and incompetent successors. They considered the Sultan just a puppet in their hands. Balban clearly knew that in the path of his despotism, the Forty would be a great obstruction.
And without its destruction, he could not achieve his goal. So he planned to bring them under control by destroying their organisation. At first, he promoted the junior Turks to important positions and placed them on par with the Forty. Secondly, he inflicted severe punishments on the members of the Forty for minor offences and reduced their importance in the eyes of the people.