The upper Himalayas is a far more barren version of the regular Himalayas map.
Unlike in the normal version, the Upper Himalayas don't feature Trade Routes. This might prevent players from building Trading Posts, but at the same time provides the ability to wall off parts of the map more easily. Also, the entire map is surrounded by cliffs, not unlike in Jotunheim, a map from Age of Mythology.
Unlike in Himalayas, Upper Himalayas contains many choke points made up from the rocky terrain that can lead players into traps and pathing issues. This makes this map ideal for turtling, as the cliffs can be easily walled off, or defended with Outposts and other similar structures. Also, Fort Drops somewhat close to enemies' positions can be an ideal way to limit mid-game expansion.
Treasure Guardians found here are:
"Gain control of vital choke points on the map to restrict your enemies' access to the most valuable resources. Players start with Town Centers in close proximity to thick forests. Beyond the trees, in the lush central valley, vast quantities of Food and Gold lie ripe for the taking. A Trade Route runs through this mountainous region, but beware, as established native settlements also dot the landscape. In the Upper Himalayas, there are no Trade Routes to obstruct wall placement."
"The Himalayas form the greatest mountain system on Earth, with more than 110 peaks rising above 24,000 feet, including Mount Everest. The range extends more than 1,600 serpentine miles from the Indus River in Pakistan to Tibet, covering more than 230,000 square miles. The flora of the Himalayans varies depending on both altitude and climatic conditions, ranging from deciduous forests in the foothills to more coniferous forests higher up. Even higher, alpine forests fill the landscape, giving way to high-altitude meadows. Scrublands lead up to the permanent snowline of the mountains. Animals such as leopards, rhinoceroses, and varieties of deer once inhabited the forests of the sub-Himalayan foothills, but deforestation has destroyed much of this natural refuge.
Forty million people live in the Himalayas. There are a combination of Indian Hindus in the sub- and middle-Himalayan valleys located in the eastern region of Kashmir to Nepal, and Tibetan Buddhists who inhabit the high Himalayas in the north. Outside influence has been minimal; but since 1950, tourism has grown into a thriving business for local economies. One million people visit the Himalayas annually for mountain activities. Most treks are conducted the same way they have been for thousands of years, with a porter and a pack animal."