Running in Tokyo, especially around the Imperial Palace on a week day, or in other big, polluted cities, is usually something I warn people not to do. However, being in Mexico City for an extended period of time forces me to make an exception, and I'm positively surprised, the city is not as bad as its reputation. The government seems to push the use of bicycles, and there is a pretty good subway.
I ran in a very small park near the centre of town, and my Garmin partly had me at under 4min/k., so I even seem to have gotten used to the altitude. I'm looking forward to the race I will do on the 14., my last day i Mexico.
Also, health food is very easy to come by here, I love the 'fibritos' (fibre cookies) they sell at the health food shop right across from my hostel.
And, last but not least, even the vendors in the street sell running magazines, so, I can improve my Spanish while checking for upcoming races!