Short answers, pulled from the story.
B. B. Lal, then director of the Archaeological Survey of India, led the first two rounds of digs between 1954 and 1972. These efforts unearthed pottery and cultural layers that suggested continuous human presence from ancient times.
The walls of Dinpanah rose under the orders of Mughal emperor Humayun in the 16th century. Sher Shah Suri defeated Humayun and took control of the unfinished project to strengthen existing fortifications and complete the outer walls.
On the 7th of October 1556 Hindu king Hem Chandra Vikramaditya was crowned inside Purana Qila. This coronation marked a brief moment of power for the Sur Empire before Mughal retaliation shifted political control back to the Mughal dynasty permanently.
Between 150,000 and 200,000 Muslim refugees swarmed inside by September 1947. The Purana Qila camp remained functional until early 1948 while waiting for transport trains bound for Pakistan.
Plans to intern Japanese living in British India began as early as July 1940 with preparations to open camps starting at least by February 1941. By December 1942 there were 2,115 Japanese internees in the camp outside Delhi.
The walls rise to a height of 18 metres and traverse about 1.5 kilometres around the site. Three arched gateways define access points including Bara Darwaza facing west and Humayun Gate to the south alongside the single-domed Qila-i-Kuhna Mosque built by Sher Shah in 1541.