Thread:Kiadony/@comment-5916303-20150313162115/@comment-1746153-20150324135918

In our case, water is the #1 cause of such sickness, rather than air. We have heavy metals in our river banks and pipes, and tap water is occasionally brown and "rusty" (so, definitely not drinkable, which is why I never drink tap water even in countries where it's suitable for drinking). In the countryside, it's because of swamps - it's not as chemically polluted as it is full of whatever decayed there over many years. But then again, I know some people who always take bottled water with them because they get sick merely from drinking water they aren't used to, such as in another place.