ABANDONED. YA-dystopian-two sisters live in a closed society where they have population control. They all end up going to jail and having to break out. Spoiler.

[Ingrid]

One sister is good and the other is a rebel. The parents arent there so the good girl always felt a need to watch over the other. One of the girls gets in trouble so she gets sent to jail. The other girl and her new boyfriend try and break her out of jail by hiding in a delivery truck but they fail and get put in jail too. The jailers make the kids fight each other and put them in a room together afterwards. They try to escape and one girl starts seeing blue butterflies and they lead her and her friends out through a tunnel. I read this book two or three years ago(2016-17). Im pretty sure the author was male BUT they may be female. I think the book cover was blue

[Kris]

Crazy House by James Patterson seems to match your description.

From the book: "Mermerized, I watched the dragonfly flit in and out of the sunlight, its glassy wings looking like tiny blue fairy lights... The guards..." | "The crowd roared as my opponent stepped into the ring."

Google search - site:www.goodreads.com "young adult" dystopian "her sister" prison

[Kris]

No response, moving to Abandoned folder.

Ingrid (OP) was last active on the site in March 2020.