So in Tibet, there are people who are from China that came to live there. They built houses and started living in the area. This is called a settlement.
Some of these people came to Tibet a long time ago because it was part of China, and they wanted to live and work there. Other people came later on because they thought Tibet was a nice place to live.
It's kind of like when you go to a friend's house and you bring your toys and things to play with. The Chinese settlers brought their own things and way of life to Tibet. They might speak a different language, eat different foods, and have different traditions.
But some people in Tibet didn't like this, because they felt like it was changing their way of life too much. They wanted to keep their own traditions and culture. So, it's a little bit complicated and some people on both sides have different opinions about it.