Aandhi

A 1975 blockbuster, this is probably the oldest--and best--example of such a film in Bollywood. It was loosely based on the life of India's first prime minister, Indira Gandhi and a Bihari politician Tarkeshwari Sinha. The film was initially banned but enjoyed a television premier nonetheless. 

Till today, it's a legendary biopic as far as Bolylwood is concerned and many consider it to be one of the most beautiful movies ever made about a woman and the tough choices she's left to contend with.