Shame on your parents for letting you walk out of the house in that. You have no respect for yourself if you think it is okay to expose yourself like that in public.

Hi Julia !
You may have issues going out in an outfit like this, but she doesn't? It's only skin. If she likes to wear this kind of shirts, or wear what some would judge to be "provocative", she is free to do so. You don't need to say how she has no self-respect what's over but you should mind your business and look up ways to resolve real problems such as pollution etc.