China-India War! Why was the territory not completely resolved at that time?

We once attacked and won and recovered 90,000 square kilometers of disputed land, but then we suddenly withdrew our troops, and the result was 20 kilometers north of the original disputed line McMahon. . . As a result, it was formally incorporated into the Indian territory, and Abang District was established, with millions of immigrants. . .

As for China, after winning, it withdrew its troops directly without consulting with India. The reason for this is the following：

1, supply problem. Because at that time, the supplies had to be transported from Tibet by yak, our equipment was too backward to carry out a protracted war, and the risk was too great.

2. At that time, China had just passed through a difficult period of three years, and its national strength was empty. However, during the Sino-Indian War 1962, the United States and the Soviet Union and their groups openly sided with India against China. If the war drags on, with the support of the US-Soviet bloc, it will be difficult for China to maintain a long-term war in the border area between China and India, and it may face the invasion of the Soviet Union (at that time, the Soviet Union was under great pressure and people had to guard against it). Therefore, India's active retreat not only lost the excuse to continue the war, but also left the Soviet-American group speechless and avoided falling into a passive situation. At the same time, China is making every effort to develop nuclear weapons. In this process, both the United States and the Soviet Union threatened to "take action" against China. In this case, it is helpful to successfully complete the nuclear program with less risk.