Short answers, pulled from the story.
B. R. Ambedkar was an Indian jurist, economist, social reformer, and politician born on the 14th of April 1891 in Mhow, Madhya Pradesh. He chaired the drafting committee of the Constitution of India, served as the country's first Law and Justice Minister, and led a mass conversion to Buddhism on the 14th of October 1956 in Nagpur.
Ambedkar studied at Columbia University in New York and the London School of Economics, receiving a Ph.D. in economics from Columbia in 1927 and a D.Sc. in Economics from the University of London in 1923. He also trained in law at Gray's Inn in London and was called to the Bar in 1923.
The Poona Pact was an agreement signed on the 25th of September 1932 between Ambedkar and Madan Mohan Malaviya, following Mahatma Gandhi's fast-unto-death in Yerwada Central Jail opposing a separate electorate for untouchables. The pact replaced the 71 reserved legislative seats allocated to depressed classes under the British Communal Award with 148 seats within a unified general electorate.
Ambedkar was appointed Chairman of the Drafting Committee of the Constitution of India in 1947, two weeks after becoming Law Minister in Nehru's cabinet. The Constitution, adopted on the 26th of November 1949, abolished untouchability, guaranteed freedom of religion, and introduced reservations in civil services and educational institutions for scheduled castes and scheduled tribes.
Ambedkar converted to Buddhism because he viewed Hinduism as an oppressive religion that institutionalized caste discrimination. On the 14th of October 1956 in Nagpur, he accepted the Three Refuges and Five Precepts and then converted approximately 500,000 followers who had gathered with him.
Ambedkar was posthumously awarded the Bharat Ratna, India's highest civilian honor, in 1990, more than three decades after his death on the 6th of December 1956. His birthdate, the 14th of April, is observed as a public holiday in many Indian states.