Border dispute between India and China is not a new thing, it has been a thing which continues through past. There was a major dispute between India, China and Bhutan tri junction in 2017 that was called doklam dispute wherever doklam was part of Bhutan and now the dispute is in Galwan Valley region of Pangong tso lake.
After all we can say that Pangong tso lake is of strategical importance and China has always evil eye on this strategic lake.
There are 8 fingure types mountain in 135 km long lake of which India controls approx 45km, and the rest is controlled by China. The main dispute is over this lake. Now let me tell you that past 1962 war this lake was half in control of India and half in China, but after the war India has lost approx 20km of area so of these 8 fingure India's post is on 4th fingure and China's post is on 6th fingure. China has already constructed a road alongside its borders and now when India started to construct Road, China has made a dispute.
China claims that this road is being constructed in its territory which is a false allegation. Now USA has been entered into this dispute and supported Indian claims because the world knows China's real face.
After all we can say that Pangong tso lake is of strategical importance and China has always evil eye on this strategic lake.