Official Survey of India maps have formally documented multiple disputed and sensitive frontier pockets along the McMahon Line in Arunachal Pradesh, bringing renewed focus to key strategic locations along the India-China boundary. The mapping covers a mountainous stretch where China's People's Liberation Army (PLA) has built structures on terrain that housed an Indian Army forward post prior to the 1962 war.

Defence assessments from a decade ago identified six disputed and four sensitive areas along the border.

The six disputed pockets are Asaphila, Longju, Bisa, and Maja in Upper Subansiri, along with Tulung La and Yangtse in Tawang.

Asaphila, Longju, Bisa, and Maja are under illegal Chinese occupation, with India now mapping Longju, Bisa, and Maja as its territory.

Key details regarding these strategic frontier sectors include:

Maja: India maintained a forward post known as Maja Camp here prior to the 1962 war. The post was vacated and became a disputed zone, where the PLA has now built structures.

Bisa: Chinese forces have constructed a road through Bisa linking two points along the disputed frontier. Sensitive Areas: Covers Thag La in Tawang, Dichu in Anjaw (already mapped), Fishtail-1 in Dibang Valley, and Fishtail-2 in Anjaw.

Both Fishtail features were occupied by PLA troops in 1962 before Chinese forces withdrew following a unilateral ceasefire, and remain unmapped. Border Incidents: A PLA transgression occurred at Yangtse in September 2016, followed by a face-off between Bum-La and Yangtse in October 2021, and a clash in Tawang in December 2022.

Additional Events: A reported Chinese road-building attempt occurred at Tuting in January 2010. Upper Subansiri recorded the capture of an Arunachal youth from Asaphila in March 2020 and five Army porters near Sara 7 in September 2020.

The broader mapping effort includes 27 locations comprising land areas, passes, a lake, and a monument. This formal documentation provides an administrative and cartographic record for New Delhi to challenge potential attempts to alter the status quo on the ground.