Z axis banding  

Subtle

What are you printing?

Z Banding is often created by wobbling or movement in the axis as the Z raises:

https://makershop.co/z-banding-z-wobbling/

https://www.nikkoindustries.com/blogs/news/how-to-fix-z-banding

https://3dprinterly.com/how-to-fix-z-banding-ribbing-in-3d-printing/

This is very subtle and might not be Z Banding.  Can you show another angle.  

More details

It increases in the top layers.

It is more evident on the left side.

It seems banding appears in equal intervals... what's inside the cylinder? Can you show us 3mf file of this object?

PS: Use "Save project" in PrusaSlicer to get 3mf file. To be able to upload in this forum, zip it first.

More data...

Nothing inside the cylinder.

Unfortunately I can not share the data.

It was just printing fine and then this lines appeared.

I always use the same filament. It happend using the same coil. I use standard PLA printing parameters.

RE: banding

I can’t really telll from the photos.  Understrusion and banding will do this but banding is usually more pronounced.  

Banding

I just tighted some screws on the X axis and untight and re-tight the Z Axis.

I also increase my next print by 5 degrees.

I just remember that this problem appeared 2 days ago when the temperatures started dropping below 5 Celsius in the night, (I always print with an open window)... Could this be related?

Possible

It is possible.  Stranger things have happended.  I would look for play in you axis also.