Who was RN Kao, 'India's greatest spy', on whom Dharma's next film is based?

Rameshwar Nath Kao, subject of Dharma Productions' next spy thriller, was appointed the founding chief of the Research and Analysis Wing (RAW) in 1968. Under Kao, RAW played an important role in Bangladesh's liberation during the 1971 War. PM Indira Gandhi's close confidant, Kao also played role in Sikkim's integration with India and helped establish the National Security Guard (NSG).