Passports, Borders, and Sovereignty: Arunachal Pradesh in Contemporary India-China Relations

This briefing looks at the Arunachal Pradesh dispute between India and China through providing an overview of present-day Sino-Indian borders, examining international law, and exploring historical claims to the region. This article was written by Amit Sriganesh Walkay and edited by Tanvi Sureka.

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Introduction

On 21st November 2025, Indian citizen Pema Wang Thongdok, whilst travelling on a China Eastern Airlines flight from London to Tokyo via Shanghai, encountered an unexpected hurdle that sparked a diplomatic row between India and China over disputed territory. Originally from the Indian-administered State of Arunachal Pradesh, which China claims as its own territory under the name “South Tibet,” Thongdok at her transit stop in Shanghai had to undergo passport checks by Chinese immigration officials before proceeding to her next flight. After it came to their attention that Arunachal Pradesh was listed as Thongdok’s birthplace on her passport, she was immediately detained and held under custody. What subsequently followed was an 18-hour ordeal at Shanghai’s Pudong International Airport, where Thongdok was held under custody by Chinese immigration officials, with her passport detained, deprived of food and water.

Through a series of posts on X, Thongdok alleged that Chinese officials had announced her Indian Passport was considered invalid and that she should immediately apply for a Chinese passport. With her initial 3-hour layover transformed to an 18-hour detention, the humiliation endured and listed by Thongdok included being mocked by immigration officials and airline staff for her Indian nationality, including facing disparaging comments asking her to obtain a Chinese passport. Moreover, Thongdok alleged that China Eastern Airlines staff coerced her to buy a brand new flight ticket in exchange for her passport, consequently resulting in Thongdok’s original Tokyo trip facing unnecessary delays and financial losses. Thongdok further recounted that after repeatedly contacting the Indian Embassy’s branches in Shanghai and Beijing, due to efforts of Indian authorities stationed in China, she was finally able to exit the airport late at night. Through Thongdok’s distressed urgent posts on X, she described her experience as a “direct insult to India’s sovereignty”, and urged Indian Prime Minister Narendra Modi and the Indian Government to raise this issue with China so as to ensure the safety of Arunachali people travelling abroad.

As a result of Thongdok’s emphatic posts on X, the sovereignty of one of India’s northeastern states was once again put into question. When probed by journalists about the Chinese stance on Thongdok’s incident, China’s Foreign Ministry spokesperson Mao Ning re-emphasised China’s lack of recognition regarding India’s control over the region, adding that South Tibet was a part of China’s Tibet Autonomous Region. As for Thongdok’s specific claims, Ning expressed that Chinese law enforcement officials acted with impartiality and due decorum and denied that any hostile and abusive action took place against Thongdok. In response, Indian Foreign Ministry Spokesperson Randhir Jaiswal reiterated that in spite of China’s denial, Arunachal Pradesh will always undeniably remain an integral state of the Republic of India.

To understand how what began as a routine transit stop escalated into a diplomatic confrontation, it is necessary to revisit the historical roots of the Arunachal Pradesh dispute between India and China, in addition to analysing its effect on the rapidly ever-evolving nature of Sino-Indian ties. At a time when Beijing and New Delhi have found themselves engaging more closely, the land disputes that pose a striking point between the two nations have the potential to become more volatile and indispensable to any future directions taken by the current world order. This is especially apparent as China and India both explore alternative routes of economic cooperation in response to the pressures created by US President Donald Trump’s punitive reciprocal tariff policies. Thus, both nations will ultimately have to come to a consensus on how best to handle the balance between mutually promising economic prospects and long-standing historical tensions.

The Origins of Present-Day Sino-Indian Borders

The fate of the current regions that make up Arunachal Pradesh was first determined during a convention held in the Northern Indian city of Simla between 1913 and 1914 between Great Britain, China, and Tibet. Popularly termed the “Simla Convention”, one of the objectives of this conference was to properly establish the international boundaries between British India, Tibet, and China. After a few days of dialogue and negotiations, a proposal for British India’s northern borders was the “McMahon Line” defined by British officer Henry McArthur, which outlined the boundary between British India and Tibet. A crucial feature of the McMahon Line was that it relegated the regions that currently make up Arunachal Pradesh as an administrative entity of British India. This arrangement was readily agreed upon by both the British Indian and Tibetan authorities, who were both willing to sign a treaty ratifying the McMahon Line as a valid international border. However, China refused to sign the subsequently negotiated treaty, claiming that Tibet was a part of China and thus “had no power to enter into treaties.” Despite China’s disagreement, the North-East Frontier Agency—the precursor of Arunachal Pradesh—was administered by British India.

After the Republic of India gained its independence in 1947, it inherited control over the North-East Frontier Agency, much to the dismay of the People’s Republic of China, with its leadership viewing the erstwhile McMahon Line as an imperialist relic that ignored China’s historical borders. As China’s Chairman Mao Zedong and his troops managed to consolidate control over Tibet during the early 1950s, the McMahon Line became a site of frequent minor skirmishes that gradually erupted into the 1962 Sino-India War. As China made rapid advances into Indian territory, capturing the Indian-claimed regions of Aksai Chin and much of Arunachal Pradesh, it ultimately declared a ceasefire and retreated behind the McMahon Line. Despite this, the McMahon Line remains a contentious issue that results in India and China taking opposing positions on the validity of their shared border.

The Verdict of International Law

When evaluating the border disputes between India and China, it is particularly important to analyse from the perspective of international law, especially regarding principles relating to precolonial disputes and postcolonial sovereignty. Referencing the particular case of Arunachal Pradesh, it becomes increasingly important to reference the principles of Uti Possidetis Juris (UPJ) and Effectivitiés (Effective Control) to effectively determine the nature of sovereignty in territories disputed by multiple parties.

Uti Possidetis Juris (UPJ) is an important principle embedded within customary international law that seeks to preserve the boundaries of colonies emerging as States. Essentially, in order to prevent ambiguity and bloodshed in the process of decolonisation, UPJ serves as a shield that guards the borders of newly-independent nations. Under this principle, nation states that are free from colonial rule inherited the borders of their previous colonial administration. This inheritance subsequently reduces the re-emergence of potential historical grievances and aggressions from other countries, thereby creating stable peaceful relations between emerging nations and their neighbouring states. Originally utilised to determine the boundaries of the newly-independent nations of Latin America, UPJ has also relatively recently been invoked in Africa regarding post-colonial border disputes, with Burkina Faso and Mali’s dispute over the Agacher Strip being settled by the International Court of Justice (ICJ) in 1986 through the referencing of UPJ. During this particular case, the ICJ stated that when “boundaries were no more than delimitations between different administrative divisions or colonies all subject to the same sovereign, the application of the principle of uti possidetis juris result in transformation into international frontiers,” in essence validating the legality of colonial-era boundaries.

Invoking UPJ onto India would—from an international legal perspective—result in the frontiers drawn by the British Indian government being rightfully inherited by the Republic of India, including the 1913-1914 McMahon Line outlined at the Shimla Convention. Whilst the erstwhile Chinese government was extremely reluctant to acknowledge the independent role of Tibet in the Convention and refused to be a party to the Treaty subsequently negotiated, it also did not provide an alternative proposal as to the exact outline of British India’s Himalayan frontier. More precisely, Chinese representative Chen Yifan initially agreed to a potential clause acknowledging the border but stating Tibet as a territory under the suzerainty of China. This highlights that the erstwhile Chinese government placed more importance on the status of Tibet rather than outlining an exact vision of their ideal border. As a result of a lack of proper Chinese engagement regarding the McMahon Line, the Line in accordance with International Law serves as a legitimate marker of Indian sovereignty, thereby including its allocation of Arunachal Pradesh within Indian territory.

Complementing UPJ, the principle of Effectivités (Effective Control) further serves as an indicator to the validity of territorial claims, with this principle outlining that the physical presence and regular uninterrupted governance of a particular territory by a sovereign nation strengthens that nation’s claim over the territory. Despite Chinese claims of control over the Arunachal Pradesh region in the lead-up to the 1962 Sino-Indian War, India has administered Arunachal Pradesh as one of its states in a continuous manner, with Arunachal Pradesh practically serving under Indian legislative jurisdiction, with regular elections and law enforcement being carried out under Indian supervision, further strengthening Indian’s claim over the region.

Historical Claims put into Practice

Despite established precedents within international law outlining potential solutions for these types of border disputes, the Chinese government presents an alternative perspective regarding their Himalayan border—a perspective rooted within claims of historical continuity rather than contemporary legal rulings. A fundamental reason for China’s refusal to acknowledge the McMahon Line and India’s sovereignty over Arunachal Pradesh lies in the status of Tibet. According to China, during the Simla Convention, Tibet legally did not have any sovereignty and thus was ineligible to act independently during treaty negotiations. Therefore, the McMahon Line is seen as a colonial relic that divided a portion of Chinese territory and subsequently does not represent a valid proof of the scope of Chinese control within the Himalayan region. In relation to the claim over the Arunachal Pradesh region, the Chinese government routinely espouses arguments relating to cultural continuity. According to scholar Neville Maxwell, the dispute over the region extends beyond geographical factors as many Chinese officials note the cultural similarities between “South Tibet” and the rest of China’s Tibet Autonomous Region, thereby providing a logically strong claim over reclaiming the region from Indian control. Maxwell further notes that the Chinese government fears that by properly demarcating the current Sino-Indian border, India’s influence over Tibet would be greatly increased, thereby threatening Chinese control over Tibet. This ultimately highlights how claims of cultural continuity are often intertwined with efforts to maintain territorial control, particularly where such control is framed as essential to political stability.

Indeed, China has often utilised instances of cultural links as a mechanism to lay claim to important religious and cultural sites within the Arunachal Pradesh region, most notably the Tawang Monastery located close to Chinese-administered territory. In a March 2023 interview conducted by the BBC, retired People’s Liberation Army Senior Colonel Zhou Bo emphasised that the Tawang tract of Southern Tibet was an especially important and undisputedly Chinese territory due to the region being the birthplace of the Sixth Dalai Lama in the 17th Century, further re-emphasising the Chinese government and military viewing the historical and cultural links between Tibet and Arunachal Pradesh as a proof of China’s rightful claim over the whole territory. This argument of historical continuity manifests itself practically through China’s previous issuance of stapled visas for residents of Arunachal Pradesh travelling to Chinese territory. These stapled visas represent the acknowledgment of Arunachal Pradesh’s citizens as Chinese, and previously have created tension between the Indian and Chinese governments. For example, during the 2023 World University Games held in Chengdu, three Wushu athletes from Arunachal Pradesh were issued stapled visas, creating unnecessary delays for the Indian team, as well as re-opening diplomatic frictions.

Conclusion

In an increasingly fragmented multi-polar international economy, both India and China are key nations bearing the consequences of US President Donald Trump’s America-First economic policies, with reciprocal tariffs placing sustained pressure on key industries and export markets. Against this backdrop, India’s growing consumer base and economic potential present an opportunity for deeper engagement between the two Asian powers. However, this engagement rests on a fragile balance as instances of border disputes and allegations of mistreatment from immigration officials threaten bilateral trust and cooperation. Thus, as India and China grapple with the possibility to pursue meaningful economic collaboration, it becomes increasingly imperative that mechanisms are developed to manage territorial disagreements without compromising national dignity or the rights of ordinary citizens. Ultimately, prioritising economic pragmatism over supposed historical vengeance offers the most credible path towards stability and mutual benefits.