When troops clash from Asia’s two principal powers, both with large nuclear arsenals, we all have cause for concern. The details of the border incident between Indian and Chinese soldiers earlier this month are sketchy and come more from Delhi than Beijing. It seems no one was killed. But the violence is a reminder of the deep tension and distrust between the world’s two most populous nations, which extends not simply to differences about several sections of their shared international boundary but to regional influence as well.

The confrontation occurred mid-winter in a mountainous area of the Indian state of Arunachal Pradesh, which is sometimes referred to by the Chinese as South Tibet. India’s defence minister accused the Chinese army of seeking to ‘unilaterally change the status quo’ by transgressing across what’s known as the Line of Actual Control (LAC), the line which divides areas under Delhi’s and Beijing’s authority pending a full agreement on the border. A spokesperson for the People’s Liberation Army riposted that a Chinese routine patrol was blocked by Indian forces ‘illegally crossing the line’. As ever, both sides say the other started it.

According to Indian media reports, as many as 200 Chinese soldiers armed with spiked clubs and taser guns – though not using firearms to limit the danger of escalation – fought hand-to-hand with Indian troops and some injuries were sustained. Indian Air Force planes are reported to have been scrambled in response to alleged violations by Chinese drones.

Sometimes these border encounters are a result of accidents or misunderstandings; more often they are result of one side, and the general perception is more often the Chinese, pushing and probing and keeping the other on edge. The LAC stretches over more than 3,000 kilometres in three widely separated sectors – for sixty years China and India have been trying, and failing, to sort out where their border runs, and to add to the difficulties in many places the LAC is not fully delineated.

The clash on 9 December occurred on a peak overlooking Tawang, a small Indian town with a historic monastery which has particular importance to Tibetan Buddhism. The sixth Dalai Lama was born there, and when the current Dalai Lama – who of course is based in India – visited the town and monastery five years ago, Beijing made clear its displeasure. Tawang has historically been part of Tibet and in 1962, during a border war, the town briefly fell under Chinese control before its troops withdrew.

A nasty brawl between rival groups of soldiers based in inhospitable terrain might not seem a big deal. But it’s part of a pattern. In 2020, there was a similar – but much more serious – clash between the two armies in the high altitude Galwan valley in Ladakh, more than a thousand kilometres west of Tawang and sometimes described as Indian Tibet. This is in the

western sector of the LAC. Again, no shots were fired, but a face-to-face encounter with improvised weapons - and reports of soldiers being shoved off narrow mountain ridges into the river below - left at least twenty Indian soldiers and four Chinese troops dead. The incident deeply alarmed the Indian government and shocked public opinion there. A few months later shots were fired across the LAC in this sector for the first time in decades. While the immediate military stand-off was defused and talks initiated, the situation there is said to remain tense and both nations have deployed tens of thousands of troops in the area.

Further back, in 2017, there was major stand-off between the Indian and Chinese armies on the Doklam plateau, in (or near, depending on your view of where the borders run) Bhutan, a small nation which has close links to India. The spark was a dispute over China’s construction of a road. Indian troops were deployed to stop the road building and eventually troops from both sides pulled back.

The persistence of these flare-ups points to a lack of political will in resolving issues about where the border runs. China may well feel that it has nothing to gain from making the concessions that would almost be certainly necessary for a full border agreement; but India has conspicuously failed to solve border problems on its other flank, with Pakistan.

Part of the problem is the legacy of the brief but bitter border war fought in 1962, a conflict that China won and cast a deep shadow over the closing years of Nehru’s time as India’s prime minister. Ever since then, China has held control of Aksai Chin, an area of almost forty-thousand square kilometres adjoining Ladakh, which is desolately remote and has barely any inhabitants. India wants this region back, and the issue has been a big irritant in relations between the two countries.

That defeat in 1962 still inflects Indian diplomacy. While many would see India’s main rival as Pakistan, the view within the Indian establishment is that while it can meet any Pakistani military challenge, the more potent threat comes from China. There is a deep unease in India about a more strident, prosperous and better armed China and what that might mean for the regional balance of power.

That has been heightened by China’s more muscular regional policy as part of the ‘Belt and Road’ initiative. The enmity between India and Pakistan is so deep that Delhi would never imagine its western neighbour to be within its sphere of influence. But the development of the China-Pakistan Economic Corridor, including about sixty-billion dollars of infrastructure projects, has underlined how deeply Pakistan is now dependent on China. Other nations in the region – including Sri Lanka and Myanmar – which India would like to regard as in its sphere of influence have also become closer to Beijing.

There is a real concern in Delhi that India will be encircled and constrained by China and its allies, and the punch-up in the heights above Tawang has added to that anxiety.

Andrew Whitehead is a former BBC India correspondent