How do the Ailao Mountains divide Yunnan into two main regions?

The Ailao Mountains serve as a primary geographic divider in Yunnan, separating the province into two distinct regions:1

• The Western Canyon Region: Located to the west of the Ailao Mountains, this area is characterized by high mountain ranges and deep, V-shaped valleys. These mountains descend from over 18,000 feet in the north to approximately 6,000 feet in the south, housing major rivers such as the Salween, the Mekong, and the Black River.1

• The Eastern Plateau Region: Stretching from the Ailao Mountains to the border with Guizhou and Guangxi, this area is part of the Yunnan-Guizhou (Yungui) Plateau. This region features a higher elevation at its western end and is defined by intermontane basins that provide significant agricultural land, as well as drainage systems that feed into the Red River and the Xi River system.1