Border clash between India and China
The Yangtse clash of 9 December 2022 occurred at night between the troops of the Indian Army and the Chinese People's Liberation Army (PLA) along their mutually contested Line of Actual Control (LAC) in the Yangtse region of Tawang in the Indian state of Arunachal Pradesh. Violent clashes ensued after the two armies confronted each other with nail-studded clubs and other melee weapons near positions on a border ridgeline in close vicinity of the revered Buddhist site of Chumi Gyatse Falls. The border incident marked the most serious clash between the two armies along their undemarcated frontier since the Galwan Valley clash in June 2020, which had led to the deaths of 20 Indian soldiers and an unknown number of dead on the Chinese side.
Independent researchers using satellite imagery found evidence of Chinese troops, numbering about 300 according to reports, from a newly constructed border village moving up towards two Indian outposts at about elevation. This provoked a clash according to the Indian government, which necessitated sending reinforcements from a forward base. 
Spiked clubs studded with nails and other melee weapons were used in a skirmish causing a large number of injuries on both sides. Six Indian soldiers with severe injuries were flown to Guwahati for medical treatment. The casualties on the Chinese side have not been formally disclosed. The Chinese PLA has claimed that the Indian troops transgressed the border while their troops were performing customary patrol duty on their side of the border. This did not receive corroboration from the researchers.
Yangtse, besides the larger Arunachal Pradesh region, had been the site of several such clashes in the period leading up to the latest incident. It had been recognised as one of the twelve contested border regions by the two countries in 1995. The border region is part of the Tawang district of Arunachal Pradesh, which is an important centre of Tibetan Buddhism, and has been claimed by China as part of its larger claim on Arunachal Pradesh, which it avers to be a part of South Tibet.
Sino-Indian frontier and geography.
The McMahon Line.
The Line of Actual Control (LAC) in the eastern sector of the border is broadly the McMahon Line agreed between British India and Tibet in 1914. Even though China regards the line as "illegal", on the grounds that Tibet was not an independent power, it agrees to abide by it as an LAC. However, the line has never been demarcated on the ground and the inadequate surveying of 1914 leaves several areas uncertain, open to dispute between the two sides. China also has an underlying claim to the entire state of Arunachal Pradesh, which it calls "South Tibet", and the claim is especially strong for the Tawang district, which was the birthplace of the 6th Dalai Lama of Tibet. The Tawang area was indeed under some form of suzerainty of Tibet at that time, but it was relinquished by Tibet in signing the agreement for the McMahon Line.
Yangtse plateau and environs.
Yangtse, the region which was the site of the clash, is essentially a plateau that adjoins the LAC. It is part of a larger area called Mago-Chuna in the mountainous and thickly forested part of the Tawang district. Yangtse is bordered to the north by an LAC that is a continuous ridgeline of high mountain peaks that range in elevation from to over . The ridgeline, with its crest reaching an elevation of over , roughly runs in a southwest–northeast direction to the Tulung La mountain pass, and affords observation over much of the surrounding area, including the roads leading to the all-important Sela pass, which provides India's gateway to the Tawang region. The Tsona Chu river meanders through Tsona County in southern Tibet before cutting through the Yangtse ridgeline near the Chumi Gyatse Falls, and entering Tawang. As of December 2022, Yangtse is one of the 25 contested border regions between India and China, and is mutually recognised as such by the two countries.
The Chumi Gyatse Falls, at about from the LAC, form the most prominent landmark in Yangtse, and mark the juncture between the two prominent ridgelines of the area; namely, the Bum La ridgeline to its southwest, and the Tulung La ridgeline to its northeast. The McMahon line at Yangtse is coterminous with the two foregoing ridgelines. It underwent a material deviation in Yangtse in 1986, when Indian troops, in retaliation to Chinese occupation of the Wangdung pasture, moved in Yangtse and occupied the stretch to the north of the hitherto prevailing line around Chumi Gyatse Falls. The McMahon line in this area was thus altered.
The control of the Tulung La ridgeline accrues an advantage of military high ground to the Indian troops in Yangtse. Indians maintain a network of layered defences in the region, with a small detachment of forward troops maintaining a chain of six forward defensive outposts on the ridgeline. Although lightly held, these serve to establish the extent of its frontier with China. Complementing the outposts is an Indian forward base of about battalion strength, emplaced about south of the ridge. India also maintains a more significant military presence in valleys adjoining the Yangtse plateau, with precarious steep dirt tracks providing the only access to the higher ground. In contrast, the Chinese hold positions at lower elevations on the plateau, which places its troops at a tactical disadvantage. However, qualitative improvements to military and transport infrastructure on the Chinese side of the border accruing from its investments has greatly enhanced its capacity to mobilize troops.
Background and significance.
The bilateral relations between India and China have for a long time been marred by considerable mistrust and suspicion, with the rancorous border dispute occupying the foreground. Whereas India has pushed for the delineation of the LAC, the Chinese have invariably demurred. Despite multiple rounds of negotiations, and an agreement in 2005 requisitioning the enunciation of parameters and principles for delineating and demarcating the LAC, the two sides have not made any tangible headway on the question.
While the McMahon line placed the border state of Arunachal Pradesh on the Indian side, China has staked formal claim to the entirety of the region, which it has esteemed as an extension of southern Tibet. The region of Tawang in particular has enticed Chinese interest for its politico-religious symbolism, besides its strategic significance.
The region is home to a significant ethnic Monpa population, who practise Tibetan Buddhism, without actually considering themselves ethnic Tibetans; it hosts the Galden Namgey Lhatse Monastery, which is India's largest, and Tibetan Buddhism's most important monastery after Lhasa's Potala Palace. It also boasts of the distinction of being the birthplace of Tsangyang Gyatso, the 6th Dalai Lama. The 14th Dalai Lama, Tenzin Gyatso, had also dwelled in Tawang, after the Chinese annexation of Tibet forced him to go into exile in 1959. India had extended its sovereignty over Tawang in February 1951. China believes that its control over Tawang would stiffen its control over the Tibet Autonomous Region, besides providing it with the gateway to the strategic Brahmaputra valley. India dismisses China's claim over Arunachal Pradesh as "non-substantial", and over Tawang as "only ecclesial".
In mid-2020, India accused China of precipitating the 2020–2021 military standoff at several locations along the LAC in Ladakh, giving rise to a series of clashes between the two belligerents. The Galwan Valley clash in June that same year, in particular, engendered the most serious border crisis since 1967, marking the first combat fatalities since 1975, with 20 dead on the Indian side and an unknown number of dead on the Chinese side. In January 2021, a face-off transpired between the two armies at Naku La in Sikkim that caused several non-fatal casualties on both sides.
Yangtse was one of the twelve regions along the LAC that a Joint Working Committee in August 1995 had recognised as disputed border area between India and China. India had established military control over the area in 1986 in the wake of the Sumdorong Chu standoff. The region is home to the Chumi Gyatse Falls. The falls are a series of 108 waterfalls on the border, colloquially described as the "Holy Waterfalls". The falls are esteemed as sacred and revered by the ethnic Monpas, who identify its genesis to a showdown between a "Bon Lama" (monk) and Padmasambhava, who is considered by the practitioners of Tibetan Buddhism to be the second Buddha. Indian officials say that the Chinese essay to disseminate erroneous notions about the birthplace of Padmasambhava, tracing it to Tibet, as against his actual birthplace Odisha, to justify their claims to the pastures in Yangtse.
In the wake of the 2020 Galwan clash, Yangtse became a region of renewed Sino-Indian focus and witnessed extensive military activities from the two armies. The Chinese undertook work on developing a Xiaokang (a Chinese term signifying moderate prosperity) border village in Tangwu, Tsona County, near to the LAC in the area, and followed it up with the construction of a sealed road connecting the village to its encampment within a hundred and fifty metres from the Tulung La ridgeline. The Indians, on their part, increased their military presence in the area, besides undertaking to augment its military infrastructure along the border, with a special focus on augmenting surveillance capabilities.
In October 2021, Indian media reported that Yangtse was the site of a brief altercation between the Chinese and Indian troops after a nigh company sized Chinese force was confronted by an Indian patrolling unit, leading to a physical brawl which was eventually defused by the intervention of local military commanders. The incident had coincided with the 13th rounds of talks at corps commander level which were to happen a few days later to find a resolution to the 2020–2021 military standoff. Writing in the wake of the altercation, a correspondent to "The Tribune" reported that India and China had both deployed an overall strength of about 3,000–3,500 troops to the area, underscoring the strategic importance that the two sides attached to the region.
An inquiry into the border incidents by "CNN-News18" found that in the two decades preceding to the clash at Yangtse, border incidents between India and China had been becoming a frequent affair in the region, leading to instances of confrontations of varying severity. These typically recurred twice yearly in the periods preceding and following the onset of winter. It noted that the Chinese had, in recent years, turned to sending a large force of several hundred troops for incursions across the LAC at Yangste with a mix of many types of melee weapons and taser guns.
Clash.
The clash along the LAC in Yangtse sprang from the premeditated initiative of the Chinese PLA, which moved a large body of its ground troops in the time leading up to the incident from its lodgement in the newly constructed border village of Tangwu to along the road leading towards its encampment on the declivity of the Tulung La ridge. Once there, the Chinese, numbering about 300 men, and armed with nail-spiked clubs, monkey fists and taser guns, advanced upon two of India's forward outposts spaced about a kilometer apart, and located at an elevation of about along the ridgeline which formed its frontier with India. Independent researchers from the Canberra-based think tank "Australian Strategic Policy Institute" in their analysis of satellite images of the area produced five days after the incident found evidence of the Chinese advance towards the two Indian outposts in the form of well-trodden paths leading uphill off the road terminus to the ridgeline.
Chinese foray towards the Indian positions in the predawn hours of 9 December 2022 prompted a confrontation with the Indians manning their outpost line on the border ridgeline, and eventually touched off an engagement that saw both sides fight hand-to-hand with an array of melee weapons. Indian reinforcements had arrived from an adjacent forward base within the first half-hour, and the fighting lasted for an hour before troop disengagement defused the situation. Local army commanders of the two sides convened a flag meeting between their border representatives at the Bum La pass in the aftermath of the incident on 11 December 2022 to resolve the dispute.
With numerous injuries sustained by both sides in consequence of the fighting, the border incident marked the most serious clash between the Chinese and the Indian armies along their undemarcated frontier since the Galwan