The two sides have not fired a bullet since 1975, but small-scale clashes have escalated in recent weeks.
When soldiers from the world’s two most populous countries, which together spend more than $300 billion on their military every year, clash, one might expect bloodshed.
But so far, Chinese and Indian troops have only thrown rocks and tried to shout each other down along an undefined and disputed border located thousands of feet above sea level.
The skirmishes are not the sort the region normally sees in the case of India and Pakistan, who fire artillery shells and use heavy weaponry on each other - often inflicting civilian casualties.
Yet, there are growing concerns that recent tensions between the militaries of China and India, along what’s known as the Line of Actual Control (LAC), will lead to a bloody fight.
“Not since 1975 has a bullet been fired across the shared border. As a result, the theory that Sino-Indian clashes are flashes in the pan and unlikely to lead to more extensive fighting has become a widely held consensus,” Professors Sumit Ganguly and Manjeet S Pardesi wrote in the Foreign Policy.
But chances of a direct confrontation have increased as the two sides try to exert influence in the region and beyond, they add.
Trouble at the roof of the world
Chinese and Indian border patrols have faced off on at least four different locations in the past month. Three of the hotspots were in Ladakh in the disputed Kashmir region, while another is at Nuka La Pass, which connects India’s northeastern state of Sikkim with China’s Tibet.
The LAC runs at 15,000ft above sea level along an undefined border that stretches thousands of kilometers from Kashmir at one end, and Myanmar on the other.
Small-scale clashes have not been unusual since 1962, when the two sides fought the Himalayan war over territorial integrity. Since then, Beijing and New Delhi have signed a number of agreements to avert any major escalation.
“No activities of either side shall overstep the line of actual control. In case personnel of one side cross the line of actual control, upon being cautioned by the other side, they shall immediately pull back to their own side of the line of actual control,” says the 1993 agreement on the management of the de-facto border.
The clashes come in the wake of a new access point that India opened in Arunachal Pradesh in India’s northeast, a region also claimed by China. India wants the access point for faster movement of troops and artillery.
In 2017, a month-long standoff on the disputed Doklam plateau at the unmarked border heightened tensions between the two countries.
China claims 90,000 sq km of its territory is under India’s control.
While India’s economy and military is many times smaller than that of China, under the leadership of Hindu nationalist Prime Minister Narendra Modi, New Delhi has been trying to redraw borders on several fronts.
And when it comes to China, Modi can count on support from China’s main rival - the United States.
Alice Wells, the top US diplomat for South Asia, says the skirmishes represent China’s attempt to assert itself just like it has done in the South China Sea.
“For anyone who was under any illusions that Chinese aggression was only rhetorical, I think they need to speak to India,” she recently told the Atlantic Council.
Last year, New Delhi revoked the autonomous status of the part of Kashmir under its control. India-administered Kashmir is the only Muslim-majority region in India and is claimed by China’s staunch ally, Pakistan.
India and Pakistan have fought wars over Kashmir and were on the brink of another last year after a suicide attack killed scores of Indian soldiers.
Beijing has stood behind Pakistan and supported Kashmiris’ right to self determination.
Another sore point between China and India is Tibet, a region which China says is its integral part. Tibet’s spiritual leader, the Dalai Lama, and the so-called Tibetan government in exile, are based in India.
A fresh point of escalation has emerged on India’s border with Nepal. For years, New Delhi played the role of a big brother when it came to Kathmandu. But relations have strained under Modi.
The Nepalese haven’t forgotten the 2015 border blockade, which led to fuel and medicine shortages.
Soon after revoking the special autonomous status of the disputed Kashmir territory, New Delhi issued fresh maps of its borders, which showed 62 sq km of Nepali territory, known as Kalapani, as its own.
Earlier this month, India’s defence minister Rajnath Singh remotely inaugurated a road in a territory claimed by Nepal. When the Nepali government protested, Indian army chief General M M Naravane said the Nepali agitation was at the behest of “someone else” - a reference that points fingers at Beijing.
The 1816 Treaty of Sugauli between Nepal and British India states that the Maha Kali River will form Nepal’s western border. But the two sides have often bickered over the actual location of the river.