Can I still do a 1/2 Ironman after 11 days in China?!?

You'll be fine. Do it.

That would be a taper period anyway, and it's not going to kill you if your "workouts" (at that point they are just maintenance anyway, not training) are sporadic.

Stay well-hydrated. Depending on what city you're in, try to stay indoors and don't breathe when outside

Is eating out required as part of your job? If so, try to eat/sample just as much as you need to be polite. If you get sucked into binge/massive course eating, eat as light and simply as you can, when you can. There is lots of very good, fresh, veggie-based food in China that you can select when you have a choice.

Rest as much as possible when you return.

Good luck!

I think you can do it.  I travel a lot for work.  You can always run.  Swimming can be really tough, because hotel pools usually are just too small.  You could try the stretch cords.    Bringing the bike with you is not normally a practical option, but most hotels have some sort of crappy stationary bike that is maybe better than nothing.

Anyway, you're not really going to lose your swimming and biking fitness in just 11 days. 

The most important thing, for me at least, is to stay healthy while traveling.  This can be tough if you are traveling a long distance and trying to train at the same time.  Eating right is absolutely crucial.  Getting sleep is absolutely crucial.  Don't take the free alcohol on the plane.  Don't eat the chocolate creme bon bons at breakfast.  Etc., etc.  OTC melatonin works well for me to get over jet lag, but I wouldn't take anything stronger because it really wrecks me, sometimes for days.  Just my experience.