Earth Ally Will Harader
It's not pure water, food or air that cleanses a Being. In fact, no physical thing is going to cleanse your Light Body, especially because your Light Body is already pure. The "impurities" that people feel lie within the mind, and those are what need to be cleansed. Poisoned thoughts leads to poisoned bodies, not the other way around.
People are going about it a totally backwards way, though most people on this Planet are living upside-down. They believe change in the physical, what they do in the lower dimensions, creates change in the Higher. Even people who don't consciously believe this still act like that's the way things work. Go tell that to any Master and they'll find it highly amusing. The Master knows which way Energy flows.
Now many, if not most, on their path to Freedom make the choice to cleanse themselves and then they change their physical habits (like what they eat, drink, etc). They feel better afterwards, but often the root cause is missed. It's attributed to what they did, instead of the fact that they made a conscious choice to improve their lives. They were clear in their intentions, and got precisely what they asked for, but they miss what truly created the change. It wasn't what they did afterwards that brought change, it was the purity of their intention. It's a case of the outer reflecting the inner, not the other way around. This is something very important to understand.