Why Asia has large areas of inland drainage?

There are several reasons why Asia has large areas of inland drainage:

1. Mountain ranges: Asia is home to some of the world's highest mountain ranges, including the Himalayas, the Karakoram, and the Kunlun Mountains. These mountain ranges block the flow of water from the interior of the continent to the oceans, creating large endorheic basins.

2. Arid and semi-arid climate: Much of Asia has an arid or semi-arid climate, with low levels of precipitation. This means that there is not enough water to create a significant runoff, and any water that does fall is often evaporated or absorbed into the ground.

3. Permafrost: Permafrost is permanently frozen ground that occurs in cold regions of the world. Permafrost can prevent water from draining away, creating wetlands and lakes that do not have an outlet to the ocean.

4. Tectonic activity: Asia is a geologically active region, and tectonic activity can create basins that trap water. For example, the Tarim Basin in China is a result of the collision of the Indian and Eurasian tectonic plates.

5. Human activity: Human activity, such as the construction of dams and canals, can also create areas of inland drainage. For example, the Three Gorges Dam in China has created a large reservoir that has submerged a number of river valleys.

The combination of these factors has resulted in the formation of large areas of inland drainage in Asia. These areas include the Tarim Basin, the Junggar Basin, the Qaidam Basin, and the Tibetan Plateau.