About 18 percent of the world’s population lives in China. And although China is also the third largest country by landmass, 94 percent of people in the country live on just 43 percent of the land.

The YouTube channel RealLifeLore explains that the majority of the population is divided by a diagonal line from Heihe in the northeast to Tengchong in the southwest. It’s not unlike the situation in Canada where 50 percent of people in the country live in just a small region near the Great Lakes. The reason why comes down to three main reasons: climate and geography, resources, and culture.

Eastern China is easier to develop due to its flat plains, and water sources like the Sichuan Basin and the Yellow and Yangtze rivers feed farmland and cities. Western China, however, has the Taklamakan and Gobi Deserts, as well as the Tibetan Plateau. These regions receive almost no rainfall because of the Himalayan Mountains, and are at an elevation and high enough longitude to cause extreme temperature swings: as low as -40 degrees Fahrenheit in the winter and then skyrocket to 113 degrees Fahrenheit in the summer.

Despite being a tough place for people, western China has glaciers, and the five rivers that begin in the region provide plenty of water to multiple Asian countries. It also has oil, and the landscape has historically served as a natural barrier to invaders. The people who live here are predominantly minorities in China.

The six percent of the population that does live in the Western part of China are predominantly minorities in the country. More than 90 percent of the country is Han Chinese, though there are 56 ethnic groups in the China. A large portion of the minority groups live in the West, including Uyghur Muslims, which China is currently being accused of genocide against.