Yellow Rain is Pollen?

The JMA believes the yellow patches are pollen, but has yet to confirm this.

http://blogs.wsj.com/japanrealtime/2011/...-in-kanto/

At this point I'm uncertain. in some areas I've heard its possible for pollen to fall like this. On the other hand, a mysterious yellow substance did far after Chernobyl.

@above: that is probably one of the most extreme examples of pulling a quote out of context that I have seen in a while. The article clearly states "The ‘‘yellow rain’’ seen Wednesday in the Kanto region surrounding Tokyo "
Unless Pokemon added tokyo into the middle of it's Kanto region, you have nothing to worry about.