What is the Black Hole tragedy and why was there no resistance against it?

A narrow lane beside the GPO building was allegedly the site of a small guardhouse which became the notorious Black Hole. We say 'allegedly' because all the information we have about the incident is based on a report by army officer John Zephaniah Holwell, the only eyewitness account that has come down to us in writing. Considering the apparent scale of the tragedy, it seems strange that no other contemporary chronicler, British or otherwise, saw fit to write about it.

Since the Black Hole tragedy is familiar to many readers, it would be enough to state the basics - on the night of June 20, 1756, nearly 150 British and Indian prisoners (including Holwell) were held captive in a 14 x 18 feet room by soldiers belonging to Siraj-ud-Daulah's army. Fort William had fallen to the nawab, and British reinforcements had failed to arrive. Crammed into that hot, stuffy, small room, the prisoners were given neither food nor water, and when the doors were opened in the morning, 123 of the 146 captives had died of suffocation and heat exhaustion, claimed Holwell. While it is fairly certain today that Holwell was exaggerating the scale of the tragedy, it is also equally true that something of this nature must have occurred on that June night. Later historians have stated that the number of prisoners was probably no more than 65, with around 45 deaths. Even if this were true, it is horrific enough. Curiously enough, Holwell and other British officials were sure that Siraj had played no part in the tragedy, and that the orders to imprison the captives in that room had not come from him.