1.- You are the one making the claims that companies are outsourced because of strict US enviromental regulation, the onus is on you
2.- I didnt brought the FTA issue you did.
So much so, people are brainwashed into believing that the EPA, the minimum wage, unions, maternal leave, health insurance requirements are job killers. Free trade is only free when everyone is competing under the same rules.
4.- I said specifically corporations, not the country in general, Mexico city isnt even known for foreign companies setting shop there.
5.- The pollution on Valley of Mexico has little to do with regulations and more to do with its geography and overcrowding.
https://en.wikipedia.org/wiki/Valley_of_Mexico#Air_pollution
Why not instead compare it to the cities that actually manufacture for the US like Tijuana, Ciudad Juarez or Monterrey.