As a foreigner, why is it that select states are absolutely riddled with water contamination while most are not (and some are pristine)? I imagine it comes down to local legislation, but surely nobody wants their drinking water polluted, so how did the legislation happen in the first place? PS: especially as Colorado and Ohio are among the worst, through my lens they seem the states that are most about protecting the…
Or alternatively, https://xkcd.com/1138/
Its also not clear how to gauge these dots. One dot may cover an enormous area or a small area. One might wonder if some instances are double counted. On the big picture level, it's reasonable down to the level of "where the people at"