The narrator refers to Ranga\’s courtyard as the Black Hole of Calcutta because the teeming masses had congested that small space into a similar sort of structure where more and more people seemed to be swallowed up as they went in. The Black Hole of Calcutta was a dungeon in the old Fort of William of Calcutta where British prisoners of war were held captive by the nawab of Bengal, Siraj-ud-Daulah. The inhabitants had to live in close quarters, crammed together in a small space. The situation was similar in Ranga\’s courtyard which had witnessed a huge turnout due to the arrival of the accountant\’s son from the city.