What is the ruling on halal nail polish?

Two things you need to verify with regards to nail polish. Number one: is it 100% water permeable? And number two: if it is 100% water permeable, how fast does it permeate? Because wudu needs an element of continuity. You can't, for example, wash your face then come back, let's say 10 hours later, and then wash your feet. No, it has to be done in a continuous motion as such. So if it takes, let's say, 10 hours to permeate, then that will not be permissible. And so those are the two key factors you need to inquire about with whatever individual company you are purchasing it from.