Black Hole of Calcutta

On the night of 20 June 1756, following the capture of Fort William in Calcutta by the forces of Siraj-ud-Daulah, the Nawab of Bengal, a group of British soldiers, Indian sepoys, and Indian civilians who had been taken prisoner were confined overnight in a small dungeon inside the fort, known in soldiers' slang as the "Black Hole." The dungeon measured approximately 14 by 18 feet and had only two windows, with thick iron bars limiting ventilation. According to John Zephaniah Holwell, a senior East India Company official who was among the prisoners, the captives were stripped of their clothing and locked in the room around 8:00 p.m. By the time the door was reopened around 6:00 a.m. the next morning, Holwell stated that only about 23 of 146 prisoners remained alive, with 123 having died from suffocation, heat exhaustion, and the resulting panic.

The events occurred in the context of rising tensions between the British East India Company and Siraj-ud-Daulah, who had ordered both British and French forces to halt fortification work at their respective trading posts amid the broader Seven Years' War. The British continued strengthening Fort William's defenses despite the Nawab's objections, prompting him to lay siege to the fort. Desertions among Indian sepoys weakened the fort's defense, and it fell to the Nawab's forces on 20 June 1756. Prisoners were reportedly assured by Siraj-ud-Daulah that no harm would come to them before being confined in the dungeon.

Holwell attributed the deaths to the "revenge and resentment" of lower-ranking jailers whose comrades had been killed during the siege, and stated that Siraj-ud-Daulah neither ordered the imprisonment nor was informed of it at the time. Some historians, including Stanley Wolpert, have offered different figures, estimating that around 64 people were imprisoned and 21 survived. Other historians, such as D. L. Prior, have suggested that 43 men from the garrison were missing or dead for reasons other than suffocation, while some accounts put the total deaths as low as approximately 18, questioning the overall accuracy of Holwell's narrative.

News of the fort's capture reached British authorities in Madras in August 1756, prompting Lieutenant Colonel Robert Clive to lead a retaliatory campaign. Clive recaptured Calcutta in January 1757 and subsequently defeated Siraj-ud-Daulah at the Battle of Plassey, after which Siraj-ud-Daulah was overthrown and executed.

A monument to those who died was later erected by the British and, after being removed amid nationalist protests in July 1940, was relocated to the graveyard of St. John's Church in Calcutta, where it remains. The precise number of dead and the degree of responsibility attributable to Siraj-ud-Daulah continue to be subjects of historical debate.