Tension is simmering along the border between two northeastern states of Assam and Mizoram with a violent clash taking place between the people of the two states at Vairengte in Kolasib district in Mizoram, injuring several people on Sunday.

This is not the first time that the residents of the two states have clashed. The border dispute between the two dates back decades.

Here’s a look at the dispute and its genesis:

The clash

Eight farmers’ huts were set ablaze by unidentified miscreants along the Mizoram-Assam border, said a senior police officer on Monday. The incident escalated tension along the border and it happened a day after a meeting of chief ministers of northeastern states chaired by Union Home Minister Amit Shah in Shillong. This is not the first time that the residents of the two states have clashed. The border dispute between the two dates back decades.

Last year, a border dispute between the two surfaced after officials from Assam’s Karimganj district allegedly destroyed a hut and plantation in an area claimed by both the states. The makeshift hut was being used by local volunteers for guarding the border to check the movement of the people in the wake of the COVID-19 pandemic. The irate mob from Vairengte (Mizoram) retaliated and set on fire about 20 temporary bamboo huts and stalls built along the national highway by residents of Lailapur, Assam.

The genesis

Mizoram shares a 164.6-km border with Assam. The state claims that a 509-square-miles stretch of the inner-line reserve forest notified in 1875 was the boundary with Assam, which disputes it.

Several rounds of talks since 1995 have failed to resolve the long-standing border dispute between the two northeastern states.

The past

The previous border stand-off had taken place in Zophai area near Bairabi town in Kolasib district of Mizoram in March, 2018 when MZP activists ( a Mizo students’ body) had tried to reconstruct a resting shed destroyed by Assam’s Hailakandi district administration.

More than 60 people, mostly students, were injured when Assam Police allegedly resorted to lathi-charge and opened fire to disperse the agitators.