Zangnan to Aksai Chin: India-China Tensions in the Himalayas

High in the Himalayan Mountains lies the meeting point of two great nations: China and India. Between them stretches the world’s longest disputed land border—one that has witnessed violent clashes throughout history. As two of Asia’s leading powers, each with distinct political systems, China and India possess the second and fifth largest economies in the world, maintain nuclear arsenals, and together are home to nearly three billion people—over a third of the global population. Naturally, how they perceive one another carries immense significance. Lately, this relationship has leaned more toward rivalry than cooperation.

On April 14, 2025, Chinese Foreign Ministry spokesperson Lin Jian declared that Zangnan is part of China’s territory and announced the standardization of names for several parts of the region. “This is within China’s sovereign rights,” he stated, asserting that assigning names is a legitimate act under international law. China maintains that India created “Arunachal Pradesh” on Chinese territory under its “illegal occupation” in 1987. Beijing strongly opposes this move, calling it illegal, null, and void. The name Zangnan (Arunachal Pradesh) was included in China’s fourth batch of standardized geographical names in March 2024, with Lin Jian reaffirming that China’s stance on the matter remains unchanged.

The border dispute is rooted in deep historical complexities. What went wrong? The answer lies in the hostile, high-altitude terrain of the Himalayas—an unforgiving cold desert of rock and ice that holds the imprints of centuries-old power struggles.

Between 625 AD and 842 AD, the Tibetan Empire was a dominant force straddling the regions now forming the southern part of China and the northern part of India. Following the death of King Langdarma in 842 AD, internal strife fractured the empire. His grandson established control over the western portion, forming the Nagari Kingdom—later known as Maryul. By 1460 AD, it evolved into the Kingdom of Ladakh. As Ladakh’s power grew, Tibet perceived it as a threat. Under the Fifth Dalai Lama, Tibet invaded Ladakh, resulting in Ladakh’s territorial losses. The conflict ended with the Treaty of Tingmosgang, widely recognized as the first formal border agreement in the region—still referenced in modern China-India border disputes.

Later, in 1720, the Qing Empire of China intervened militarily to depose the Dzungar ruler of Tibet and installed the Seventh Dalai Lama, Kelzang Gyatso, initiating Chinese indirect rule over Tibet—a control that persisted under Qing protection.

In 1819, the Sikh Empire annexed the Dogra Empire and later conquered Ladakh, bringing western Tibetan regions under Sikh-Dogra rule, while eastern Tibet remained under Chinese influence. Following 1842, the Sikh-Dogra forces launched expansion campaigns into Chinese-controlled Tibetan territory. This conflict concluded with the Treaty of Chushul on September 17, 1842, signed by representatives of Tibet, the Sikh-Dogra rulers, and China. This treaty recognized the pre-war traditional boundary between Ladakh and Tibet. Today, India cites this treaty to argue that Aksai Chin historically belonged to Ladakh, while China rejects this claim, reiterating that Ladakh was once part of the Tibetan Empire.

During British colonial rule in India, rising tensions with Russia—known as the Great Game—fueled geopolitical anxieties. Fearing Russian advances through the Sikh-Dogra-controlled Kashmir and Ladakh, the British waged war against the Sikh Empire in 1845. After the war, Gulab Singh acquired Kashmir from the British. Seeking to secure the northern frontier, the British initiated the Great Trigonometrical Survey of Ladakh in 1855, led by W.H. Johnson, who proposed the Johnson Line, placing Aksai Chin within Indian territory. China rejected this proposal, maintaining that ancient frontiers should remain untouched.

In 1899, the British proposed the Macartney–MacDonald Line, which placed most of Aksai Chin under Chinese jurisdiction. However, China did not issue any official response. Further attempts at resolving the border came during the Simla Convention in 1914 between British India, Tibet, and China, proposing the McMahon Line. This line split Tibet into “Outer Tibet” (under the Dalai Lama) and “Inner Tibet” (under Chinese control). Although signed by British and Tibetan officials, China refused to sign, rejecting the division and asserting full sovereignty over all of Tibet.

After gaining independence in 1947, India inherited these British-drawn borders. In contrast, following the 1949 formation of the People’s Republic of China, Beijing repudiated all previous treaties, declaring them invalid. Mao Zedong declared Tibet an integral part of China, and by 1950, Chinese forces entered Tibet. The Dalai Lama later fled to India, settling in Dharamshala, Himachal Pradesh.

China began constructing infrastructure through Aksai Chin, facilitating troop and logistics movement. In October 1962, the Sino-Indian War broke out over Aksai Chin (western sector) and Arunachal Pradesh/Zangnan (eastern sector). After a brief but intense conflict, China withdrew from Arunachal Pradesh but retained control over Aksai Chin. Tensions persisted for decades, leading to agreements such as the 1993 Agreement on Peace and Tranquility, the 1996 Confidence-Building Measures Agreement, and the 2003 Declaration on Cooperation. These agreements pledged both sides to avoid force within 2 km of the Line of Actual Control (LAC), though the LAC remains ill-defined and contested.

After years of relative calm, border tensions escalated again. A standoff occurred in Depsang Valley (2013), followed by a face-off in Chumar during President Xi Jinping’s visit to India. The most notable confrontation took place in Doklam in 2017, a 73-day standoff at the tri-junction of Sikkim, Bhutan, and China. In 2020, violence erupted in the Galwan Valley, resulting in the deaths of 20 Indian soldiers. Since then, both nations have increased military presence, infrastructure development, and conducted multiple rounds of military talks, though minor clashes continue in Tawang (Arunachal Pradesh), Naku La (Sikkim), and near Bhutan.

The two countries still cannot agree on the precise location—or even the total length—of the border. In 2024, during the Munich Security Conference, an Indian spokesperson asserted India’s strength and capability to handle any incursion, saying India would stand firm against “the dragon.” Meanwhile, China’s Foreign Minister avoided directly referencing India but reiterated China’s stance: “With a vast territory and over a dozen neighboring countries, China faces complex disputes inherited from history. We remain committed to consultation and peaceful dialogue.”

Shitao Li, head of DW’s Chinese service in Bonn, Germany, emphasized that the border conflict is central to the rivalry. “No government,” he noted, “will openly say, ‘let’s compromise by giving away land in the name of peace.’ Such a resolution grows more unlikely with time.” Similarly, Qian Feng of Tsinghua University’s National Strategic Institute told Global Times that “India has no right to question China’s legitimate sovereign actions,” which, he argued, are in accordance with international law.

These entrenched positions reflect the depth and intractability of the dispute—where diplomacy is overshadowed by decades of mistrust, and even diplomatic statements become battlegrounds of rhetoric.

China’s claims over Aksai Chin, Zangnan (Arunachal Pradesh), and Sikkim are rooted in a combination of historical presence, cultural ties, and strategic calculations. In Aksai Chin, China rejected both the Johnson and McMahon Lines, favoring its historical interpretation, citing connections between Tibet and Xinjiang. In Zangnan, it invokes cultural and spiritual ties to Tibet, including the birthplace of the Sixth Dalai Lama and the significance of the Tawang Monastery, symbols of Tibetan Buddhism and national unity. Strategically, the region’s proximity to Bhutan and the Siliguri Corridor (India’s “Chicken’s Neck”) adds military value to China’s southern defense.

Ultimately, both India and China remain entrenched in a high-stakes competition over Zangnan (Arunachal Pradesh), with history, culture, geopolitics, and national pride colliding in a perilous standoff. Though not in open war, the situation is far from peace—a geopolitical chess match playing out in the thin air between Aksai Chin and Zangnan.