Dystopian Science Fiction. A city is built upwards instead of outwards. Upper class lives at the top, lower class at the bottom.

[Cara]

To go into more detail
Read it around 2014?
Its a detective who needs to find someone. The "slums" used gas lamps or something that is toxic and I think it killed his mom. He goes into detail about it constantly. I believe in the first chapter he goes to a really rich house where he notes about there being sunlight.

I saw that someone else asked this but was abandoned so trying again

[SBC]

The Roar? Someone was looking for something similar and that was the answer here - https://www.goodreads.com/topic/show/...

[Cara]

no, unfortunately not. it was one detective guy and not siblings. It was written from his perspective

[Rainbowheart]

Some previous threads that might be helpful?

https://www.goodreads.com/topic/show/...

https://www.goodreads.com/topic/show/...

https://www.goodreads.com/topic/show/...

https://www.goodreads.com/topic/show/...