In the past I've made posts about draining the Bohai Sea over 50 years to create new land the size of the UK, and diking/damming/draining Sundaland, to reclaim an amount of land equal to the Americas (over 2-4 centuries)

Here, I state that focusing on the Taklamakan desert (the oval depression in Xinjiang) specifically offers some advantages

1. the population of Xinjiang is already one of the fastest growing in China. So there's already a natural incentive to focus on this area.

2. The Taklamakan is huge, 180,000 sqmi. For reference, Germany is 140,000 sqmi, and Turkey is 300,000.

Takla is also basically the size of the North Chinese plain, but with one very important advantage. Note the BROWN color on the map, this means higher elevation (green is low). Takla is much higher than sea level.

The REASON for this highly elevated, but uniformly flat land, is the millennia of sediment deposits laid there from the mountain-fed rivers surrounding it. In other words, the Taklamakan desert should have some of the BEST and also MOST soil in the world (just add water)

3. A secondary to the "mountain fed rivers" from above--the fact that it is surrounded by mountains on all sides guarantees moisture stability.

If you were to put water in the Sahara, it may dry up quickly, because of rain/wind patterns, because the Sahara is a very open space. This is not stable.

But if you were to put a bunch of water in the Taklamakan, any evaporated moisture would simply hit the surrounding mountains and condense (leeward and windward), returning back into the basin. Basically, it should be a "one-time fix".

The only issue is physically desalinating and moving that much water into the basin. But once that's done you'll basically have the most fertile and resilient green space on earth.