That is the exact problem with the city of Dinipro.
Citizens of this city high in the sky imagine it so fully in their minds that no one there needs to open their eyes to walk the streets and live their normal lives. But if one makes the mistake of opening their eyes and tries to see the city directly, they would immediately fall through the clouds to the ground deep below.
Where is the city of Dinipro from? It's not one of the 55 from this book and I can't find anything about what you're describing on the internet.
On that note, I'd quite recommend the Coyote vs. Acme movie, some great world building there.