people usually have nothing under undeware 
…and because she is from profile there is actually nothing “prohibited” you could see on her ass even if she would have just tanga and the brest is fully covered.
What is censored if - genitalia - you do not see them, female breasts/nipples - you do not see them, Ass from behind where you see the “line” (sorry not native English speaker) - but you do not see this