The beginning of tensions and violence in Punjab can be traced to a time nearly six years before Operation Blue Star. But the foundations for the rift were laid nearly 11 years before it.
If an exact date was to be fixed for the beginning of Violence in Punjab, then it would be 13th of April, 1978. In a scuffle between Akalis and Nirankaris, two sects in Sikhisim, 13 Akalis were killed. This incident marked the rise of Jarnail Singh Bhindranwale. But, prior to this incident, a resolution was adopted by the Shiromani Akali Dal in 1973. The resoloution was the Anandpur sahib Resolution, which demanded autonomy for the state of Punjab. Bhindranwale took upon himself to implement the aims of the resolution.
Even though Operation Blue Star was launched by the central government to tackle Bhindranwale, and the operation ultimately led to the assassination of Indira Gandhi, it is the Congress which was responsible for bringing Bhindranwale to the forefront of Punjab politics.
In the elections following the emergency, the Congress lost power in Punjab and the Akali Dal formed the government. Giani Zail Singh was a prominent leader of Punjab at that time. To counter the growing power of the Akali Dal, Zail Singh, along with Sanjay Gandhi, decided to propel a counter force. For this purpose, Jarnail Singh Bhindranwale was selected.
But once he gained power, Bhindranwale became a force they could not control.
Watch how the political power plays lead to Operation Blue Star and the assassination of Indira Gandhi, in the 14th episode of Pradhanmantri.