Short answers, pulled from the story.
The Poona Pact was a negotiated settlement signed in September 1932 between Mahatma Gandhi and B. R. Ambedkar that increased political representation for the depressed classes, now known as Scheduled Castes. It was signed by 23 people, including Madan Mohan Malaviya on behalf of Hindus and Ambedkar on behalf of the Depressed Classes.
The Poona Pact was signed on the 24th of September 1932, at 5 pm, inside Yerwada Central Jail in Poona, India.
Gandhi, then imprisoned by the British, began a fast unto death to protest British prime minister Ramsay MacDonald's Communal Award, which had granted separate electorates to the depressed classes. Gandhi argued that separate electorates would vivisect and disrupt Hinduism.
The Poona Pact reserved 148 seats for the depressed classes, replacing the Communal Award's original allotment of 80 seats. This was nearly twice the 71 seats the Communal Award of August 1932 had offered.
Twenty-three representatives signed the Poona Pact, including Madan Mohan Malaviya for Hindus and B. R. Ambedkar for the depressed classes. Gandhi himself was not a signatory, but his son, Devdas Gandhi, signed the document.
Critics say the reserved-seat system descended from the Poona Pact now dilutes the influence of Dalit members of Parliament, since many represent constituencies where Dalits are a minority. Writers including Perry Anderson and Arundhati Roy have also questioned whether Gandhi coerced Ambedkar into the agreement, though historian Gitanjali Surendran says Ambedkar was content with the outcome.