@Joe Shearer - have they breached the LAC in areas which they don't claim?
Apparently not.
What happens is this: The Indian claim line runs east of the Chinese actual locations. The Chinese claim lines run west of the Indian actual locations. Each side insists on patrolling up to its claimed line, and that necessarily takes it beyond the opposition positions. It is at these times that patrols find themselves face to face with each other, with a variety of reactions and responses.
The Chinese, however, have a habit of salami-slicing: of improving their positions by minute amounts every time a new unit takes its place on border defence duties. This has resulted in some unexpected bulges in the actual locations; the Indian locations have stayed the same, the Chinese locations have inched forward in a number of places. Moving an actual location back to the original spot is far more difficult - and contentious - than meeting the others on a routine patrol.
The provocation is not entirely Chinese. The great untold story of this border is the extensive infrastructure build-up that has taken place on the Indian side. After decades of labouring under a weird theory that improving infrastructure (= roads) would improve the prospects of an attacking force, the Indian side has actually expanded and extended its network considerably, not merely in length, but in terms of load-bearing capacity. At last, we have understood what the Chinese understood and implemented from 1950 onwards: roads mean presence, presence means domination, domination means victory. The Chinese side is naturally and correctly alarmed, and is reacting to it, among other reasons in order to pull down the Indians a peg or two when they need to break through the wall of resistance building up against China in international affairs.
India's silence or even tacit approval of freedom of the seas cruises by the USN in the South China Sea, her refusal to return Taiwan to the dustbin of history, as had been Indian policy from 1950 onwards, after Mao won and Chiang lost, her refusal to certify China's integrity during the Covid-19 crisis, her return of Chinese PPE as defective and malfunctioning, all have come together to exasperate the leadership in Beijing, and this exasperation seems to have trickled down the ranks and seems to be responsible for much of the bellicosity on display at the borders.
