Here's why:

* Size: It covers an area of approximately 2.5 million square kilometers (965,000 square miles), making it the largest and highest plateau in the world.

* Elevation: It has an average elevation of over 4,500 meters (14,764 feet) above sea level.

While the question asks for the *second* largest plateau, the Tibetan Plateau's immense size and elevation make it the clear leader, leaving no room for a clear second place.