Mausam (1975)

While studying for his exams in Darjeeling, medical student Amarnath (Sanjeev Kumar) has a passionate fling with a pretty local named Chanda (Sharmila Tagore). He vows to return to her but never makes good on his promise. Fast-forward 25 years, and Amarnath is back in town, where he's shocked to learn that his affair with Chanda produced a daughter. But the surprises don't end there: Furthermore, he discovers his long-lost child is a prostitute.