Some of the Sikh groups fighting for a seperate Sikh nation such as Babar Khalsa had resorted to terrorism and were responsible for bombing of Air India flight 182 and Narita International airport bombing in the 1980s. They claimed to be fighting the persecution of Sikhs by Hindus in India. Their activities peaked afterr the 1984 anti-Sikh pogromĀ in India. By 2020 these groups had lost much of their support which was not huge to begin with.

https://hinduexistence.org/tag/namdhari-sikh-foundation/