China has branded India’s formal mapping of 27 locations in Arunachal Pradesh “illegal, null and void”, reviving a decades-old territorial dispute days after New Delhi placed the sites – mountains, passes, settlements and a high-altitude lake – on Survey of India maps. Chinese foreign ministry spokesperson Guo Jiakun made the comments on Monday, again claiming the region as Chinese territory under the name “Zangnan” and rejecting India’s use of “Arunachal Pradesh”.India marked the 27 locations on Friday (August 7), treating the exercise as a routine assertion of its own administrative authority.

Beijing, however, saw it differently: the sites, it said, sit within territory it claimed as its own. One of the contested territories in the list is Longju, a settlement that has remained under Chinese control since Indian troops withdrew from it in 1959 – raising a dispute over whether India’s cartography claims extend beyond the areas it currently controls.India’s responseIndia’s Ministry of External Affairs spokesperson Randhir Jaiswal told a briefing on Tuesday (August 11) that Arunachal Pradesh remains an “inalienable and integral part of India” and that “nothing can change this indisputable reality”, echoing how New Delhi has argued against China’s renaming exercises since at least 2017.

The Home Ministry, which ordered the mapping in consultation with the Arunachal Pradesh government, has framed the move as a clarity exercise rather than a new claim, saying it is meant to aid “accurate recognition” of the sites rather than alter facts on the ground. The terse exchange has come at a delicate moment – barely a year after the two militaries reached a 2024 disengagement understanding along the Line of Actual Control, and days after a China-India border trade route at Shipki La reopened after a six-year suspension — but ran into difficulties within a week of restarting.

Although the two governments are simultaneously trying to normalise ties on some fronts while the Arunachal dispute continues to resurface as an unresolved flashpoint.The dispute is less about physical control, which has changed little in decades, and more about competing efforts to entrench claims through maps, names and infrastructure. China insists that India has unlawfully turned what Beijing calls South Tibet into a state; India maintains that Arunachal Pradesh is an integral and inalienable part of the country, and that China illegally claims roughly 90,000 sq km of Indian territory in the state. “India’s move of attempting to replace names long used by China with its so-called ‘standard names’ is “illegal, null and void”, Guo said in a statement on the foreign ministry's website. The row traces back to the McMahon Line, the India-Tibet border drawn by Sir Henry McMahon in 1914, which China refused to endorse at the time.

Arunachal Pradesh matters particularly to Beijing because of Tawang, home to a monastery regarded as the birthplace of the sixth Dalai Lama and one of Tibetan Buddhism’s most important centres outside Tibet. But China’s claim extends to the whole state, which India formally established in 1987 as part of its north-eastern administration.Tensions over the Himalayan frontier hardened in 1959, as the newly-independent India consolidated its administrative border and China tightened its grip on Tibet, culminating in the 1962 war, when Chinese troops crossed the McMahon Line and advanced into what was then the North-East Frontier Agency before withdrawing.

The border has remained unresolved since, with both sides holding differing views of where the Line of Actual Control runs. Further escalation in 1986–87 nearly tipped into armed conflict before de-escalating, and confidence-building agreements followed in 1993 and 1996. China has issued standardised Chinese names for Arunachal locations periodically since 2017, with further batches in 2021, 2023, 2024 and, most recently, April 2026. A May 2025 batch of 27 names – 15 mountains, five settlements, four passes, two rivers and a lake – was dismissed by India as “vain and preposterous”, in a statement by Indian foreign ministry’s spokesperson Randhir Jaiswal. New Delhi’s latest mapping move comes even as both governments have been working to stabilise ties since a 2024 disengagement understanding along the Line of Actual Control – underscoring how the Arunachal question continues to resurface as a persistent irritant even when broader relations are on a more even keel.