How do I make a background continuous of endless with player movement?

Please suggest how to implement the top down scrolling in Unity in which the player moves vertically but never leaves the background image. I have watched Top Down tutorial on Unity website but in that case only the background repeats itself whereas player is not moving vertically. As you can see in the image below, the balloon continues to fall down and ultimately leave the background sprite (sky blue) behind and is lost in the Unity default blue space. Please help me solve this problem.

@Landern
@supernat

unity scene has limied size, so if you need unlimited size, you need to freeze the object and scroll the image. and of course image should be tiliable.

it comes to my mind that you can also make use of “teleportations”, so when object reaches certain collider in the buttom, it is instantly moved in the topmost position with camera, but you will need to setup this properly, so the teleportation is not noticable at all.