Rentahamster
Rodent Whores
It's impossible to have a city with 1M residents with or without severe gridlock in SC2013.
Actually, it's possible.
On a whim, I decided to try out the challenge on the EA SimCity forums (get the highest pop on Tamarin Island).
http://forum.ea.com/eaforum/posts/list/9846105.page
I was able to shove over a million poors in that space. Not bad I guess. The top guy on the forum hit 1.4 mil, though. Impressive. I probably could have hit that too, with a different layout and more time.
edit: squeezed out another 100 thousandish
http://forum.ea.com/eaforum/posts/list/60/9846105.page#31377511