What can I do if someone smokes crack on the one line

Not a hypothetical by the way yesterday was coming home after having a great time at pride fest at Cap Hill and someone smoked crack in front of me, wasn’t paying attention until a terrible smell hit my nose then I moved away. Never smelled burnt back before so fun first for me.

What can I realistically do in this situation, obviously I’m not trying to get stabbed but I also that’s not acceptable in society so is there any thing I can realistically do here

Edit: based on smells of drugs a user informed me it was meth not crack. My apologies