Why did China withdraw its troops after the victory of the Sino-Indian War in the 1960s?

Now, the Indian still occupies the south of China. Why did China quit the territory of China after winning?

Please give me the details of the Sino-Indian war!

thank you

Unlike what you know from the official, I'll give you a real reason.

First of all, southern Tibet is a disputed area. What is the controversy in this regard? To put it simply, historically, China and India have never ruled this place effectively. Although everyone says they have sovereignty over this place, in fact, no country has really owned this place.

This area is divided into three sections, namely the eastern section, the middle section and the western section. After our victory that year, we have been occupying the central and western sections. Only the eastern section retreated. Why are we retreating? Because the place we occupy is highland. ...