This was announced back in 2012 and is supposed to be completed by 2021 but, based on a quick search, I haven’t been able to find anything to confirm that.

It has many of the features of Oasis Cities in that it is built within a park, is designed to be “mostly” car-free and will have a similar pop’n density (if the surrounding park is included in the total area)

The city’s perimeter is defined by a clear edge, from which the city center can be reached on foot within 10 minutes. An extended recreation system connects the pedestrian network to trails that run through the green buffer and surrounding farmland. The infrastructure and public-realm networks include electric shuttles, plazas, parks and links to the recreation system. As a primarily pedestrian city, only half of the road area is allocated to motorized vehicles. All residential units will be within a two-minute walk of a public park.

“a 1.3km2 circle surrounded by 1.9km2 of farmland and parks, where residents won’t need cars because everything is within a 15-minute walk of the city centre”.

The 80,000 people expected to live in the Great City would give it a population density of 61,538 people per square kilometre.

That’s comparable to some of the most densely-populated city districts in the world — like Paris’ Le Pré-Saint-Gervais (63,876) or Manila’s Malabon (59,767). In London, the most densely populated boroughs in the inner city have a density of around 10,000 people per square kilometre. The entire Great City complex — urban circle and surrounding open park/farmland — is roughly the same size as Hampstead Heath.
The emphasis is on fitting as many people as possible into as small a space as possible while still making a city that “quite simply, offers a great place to live, work and raise a family”.

https://www.wired.co.uk/article/china-great-city