4. 1984 Anti-Sikh riots : Several thousand innocent Sikhs were killed after riots broke out on October 31, 1984 after the assassination of the then prime minister Indira Gandhi by her two Sikh bodyguards.
This was preceded by Operation Bluestar by the Indian army to flush out Khalistani militants led by Jarnail Singh Bhindranwale from the Golden Temple in Amritsar.