" Operation Falcon (1986-87) : Early September 1986-Following the discovery of a PLA camp in Wangdung in the Sumdorong Chu Valley NE of Tawang, a battalion of the Indian Army's 5 Division occupied the heights around called Lungro La and Khypo. Here you see PLA officers & soilder`s were halted & were warned and realised that there was no way up! "
Arjun Subramaniam
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In 2020 similar but in more aggressive way things are going down, black top and helmet top ladakh..
China considers all this Indian aggression stemming back all the way to the 1950s. The only way through this impasse is either both sides settle on whatever mutually tolerable/acceptable outcome or they both go to war and settle it with winner keeps all. India never even bothered discussing mutually demarcating this line and rejected offers to talk since Nehru. India insists on their own and British demarcated lines. But at the same time India recognises its deficiencies in the military option and will not fight a war to settle it. So it's just this annoying drawn out poking which India has with Pakistan as well. Where Indian troops will go into what China considers it's territory (and India reckons is its own) and celebrate with media stories then leave as soon as PLA come to shoo them away. This repeats until one confrontation gets violent and the media laps it up.
It has to be said though that this was the old pattern with minimal violent confrontations. However since April or perhaps even a bit earlier, China has shown more resolve in unilaterally settling the border as they see it. That is the case on the ground at the moment, albeit with Indian resistance and challenges such as what happened a few days ago I'm sure. But this is to be expected since PLA has made these unilateral moves.
Why is this happening though? Well it seems CCP is tired of the poking around and since India unilaterally decided to make several provoking moves* CCP sees fit to respond and act in Ladakh.
*1. Article 370 threatens Kashmiri territorial issues which China has more than a stake in (2018)
2. Threaten CPEC and related routes (entire existence of CPEC)
3. Demonstrated India's position on China re BRI and CPEC with the Doklam road issue (2017)
4. Heaping in with China's actual adversaries in putting political pressure and blame for Covid and flirting with joining Quad alliance against China. (2020)
5. Continuous salami slicing tactics resuming from 20th century.
6. Presenting Aksai Chin as Indian territory... can you imagine India's reaction if China presented Assam and Sikkim as China's territory? We're not even talking about Arunachal Pradesh. Aksai Chin isn't disputed.
Seriously enemy status appreciated by now don't you think? CCP does to enemies what everyone would, work against their interests. Any surprise CCP unilaterally made military moves in Ladakh to firmly settle the border dispute?