Most of the world's wars and conflicts were caused by the British. Whether it is the independence of Northern Ireland and Scotland that are spiraling out of control at home, or other international disputes, this is ample proof of this. That's true"Lift a stone and shoot yourself in the foot"。During the British rule in India, we also mentioned earlier that the British quickly rose from a small kingdom to an empire, and the key to this was their successful conquest of India. It's like the second largest country in the world becoming theirs"Cattle"。This is not an exaggeration, in the eyes of the British, India is like a white cow, providing them with an endless supply of industrial raw materials, a supply of soldiers, and a vast dumping market. India provided Britain with a lot of war resources and manpower, and almost every British foreign war had Indians and Sikhs behind it. Even until now, the Sikhs have remained loyal to the British. The one who wears the turban is a Sikh. 
India is so important to Britain that Britain has to take care of its own cows, and Britain has put forward a strategic concept called "three buffer zones, one inner lake, and two concentric circles", which is more vague to say, just look at the map:
Like the ** people, the British are also "buff maniacs", ready to put a buffer zone around the cows. In this context, Britain began to expand to the **, and even coaxed, ready to take away the whole **, which they called "Outer Tibet". And as you know, after 1820, the Qing Dynasty was no longer good, and then lost again in the Opium War. **Originally, he was still very loyal to the Qing Dynasty, but now he was oppressed by the British, and the Qing Dynasty couldn't help much, and the British even invaded Lhasa in 1904, burning and looting everywhere, and the Qing Dynasty was almost finished, so naturally there was no way to manage it**. The pro-** forces in the territory are increasingly being abandoned, and the pro-British figures have come to power and joined forces with the British to put pressure on the **. By 1914, at this time, China had become Beiyang Yuan Shikai**, and Britain asked *** to assign ** to Britain as a colony. Of course, Yuan Shikai didn't dare to agree, the Qing Dynasty was like that, and he still kept Xinjiang**, if he lost **, this would be a notoriety in the history books, so he refused the British request. However, the territory that is nominally still ** is actually basically not listened to, and Yuan Shikai does not listen to Yuan Shikai's words, and he signed a contract with the British in private. This treaty is a secret treaty, what is in it, no one knows, the British later said that there is a line, called the "McMahon Line", I found a picture on the Internet, which is the following one:
The orange and yellow area in the picture above is "southern Tibet", and the green area is now Aksai Chin, the British said that in 1914, the authorities gave the yellow area to India (India was Britain at that time), and McMahon was a British diplomat, but China was unable to fight with Britain at that time, so it could only endure.
However, from this time on, there is a key issue, all the ** in China, from the Qing Dynasty to the Beiyang, and then to the **, until the new China, has never recognized the legitimacy of this line. But the Indian and British feel that since it is signed by the ** people, it is signed by the Chinese, so it is effective.
The differences between the two sides here laid the groundwork for future conflicts, and it stands to reason that there were conflicts at that time, but for the next hundred years, China has been fighting, the Opium War, the Taiping Heavenly Kingdom, the Hui Rebellion, the Xinhai Revolution, the ** War, the Central Plains War, the Northern Expedition, the Anti-Japanese, the Civil War, and ignored them.
Let's talk about how China taught India a lesson in the 1962 Sino-Indian conflict.