Hauz Khas gets its name from this large water reservoir. Originally it was constructed during the reign of Alauddin Khalji and was known as Hauz-e-Alai during those times. It lay to the western side of his capital city, Siri. Hauz-e-Alai, a man-made water reservoir used to be the principal source of water supply in Siri. Due to no proper maintenance after Alauddin Khalji’s death, silt blocked the water supply. Firoz Shah Tughlaq during his rule restored it and this tank came to be known as Hauz Khas or Royal Tank. The view from Madrasa-e-Firuz Shahi of this water reservoir looks so astonishing. Surrounded by greenery and the sweet voice of birds give a different feeling and pleasure.