As many people commented, it’s a gap between concrete slabs. it is more pronounced in the basement of my building, because they didn’t try much at cover it.
Btw, I photographed it earlier to demonstrate the great work engineers done neatly guiding wiring and piping.
Edit: provided photo as a link
https://photos.app.goo.gl/RCsS9fJmFnp4XGbR9