FYI, I found this document dated Jan 2015. Mexico recognizes the importance of establishing availability of this diesel fuel and exhaust fluid ahead of the proposed January 1, 2018 implementation...
I am going to bring a jar of US diesel down this fall. I am curious to see if there is a visible difference. I suspect staions will not advertise if they have ULSD, so it would be nice to know if you can tell by looking at it.