Koshbel Duban is a high mountain pass at an elevation of 4.279m (14,038ft) above the sea level, located in southwestern Xinjiang, an autonomous region in western China.
The road to the summit is called 219 National Road, also known as Tibet-Xinjiang Highway. Construction of this road started in 1951. It was completed in 1957 and fully paved in 2013. On this road, also known as the "Sky Road" in Chinese, you're firmly on altitudes over 5,000m. For an unacclimatized person this can be fatal. The breathtaking scenery ranks as some of the most inhospitable terrain on the planet. Expect many stretches with no water or food for tens or hundreds of kilometres, dozens of high passes, no shower or even a wash for weeks, and nightime temperatures of -25 degrees C or lower. The views on the summit are amazing. Interesting scenery with desert like valleys and snowy mountains in the background.
The road is long and arduous and crosses several mountain passes of 5,000, 4,000 and 3,000 meters. This road passes through remote areas, so you need to be prepared. Despite its reputation for running through terrain that is by and large uninhabited, the G219 does pass through a number of important historical and religious sites. If you do choose this route please check up to date information. It's a windy place and it's one of those places where you can feel hard winds coming from two directions at the same time. It’s a great climb with many switchbacks.
For your safety, be sure to check the weather forecast before you begin your trip. The extremely high altitude of Tibet makes the winter seasons extremely harsh, marked by extreme cold with gust of strong winds, blowing almost all the time. Due to the high elevations and exposure, the road is subject to strong winds and rapid weather changes. Be prepared for the cold and wind! Therefore it is better to avoid any trip to Tibet during winter. Half of the roads remain closed due to heavy snowfall. The atmosphere becomes extremely arid and almost intolerable. Even in summer you can confront with snowy days. There are truck stops along the way, about a day’s travel apart, but it’s wise to bring food and a sleeping bag. A tent can be useful in emergencies. Monsoon always begins from July and end up with August. It rains a lot during Monsoon time and it makes self-driving travel difficult to handle with. And remember, in China, a lot of websites are censored so you won’t be able to access any url you want (especially if Tibet is mentioned).