Environmental protection in China

The best thing everyone can do is not use the little plastic bags the grocery store give you for one yuan. Those plastic bags will stay around forever! Instead pay 6 to 9 RMB for a re-useable bag and take it back whenever you shop.
Take the Metro or subway as much as possible. A taxi is just another car for four people. If you have larger groups or items to move request a small "bread truck" cab. They cost a bit more but you can move a lot of stuff with it. If the weather is nice, walk to your destination is good for health and the environment.
I am sure there are more good things to do but they are my pet "green" things.

I always carry a backpack with extra bags in it for shopping.
I'm more apt NOT to get my food to go after living in China. I threw away styrofoam containers on a regular basis in USA.
I save toilet tissue cardboard rolls to give for art projects, although it's better to get the toilet paper without the cardboard roll.
I take the elevator that I see is closest to my floor even if I have to walk a ways to find one.
I do not wash my clothes as often anymore, unless they are dirty, I wear more than once.
I do not take hour Long tub full of water baths anymore.
I plan to start an herb garden in our apartment.
I walk everywhere!!!

I have just visited a ship (work) discharging 141,000 tonnes of coal from Australia to burn in a power station. I pass the power station and see the plumes of black and white smoke poring out causing it's own cloud above! I think, "no wonder China has been generally colder this winter (compared to other years), there must be a great big hole in the ozone layer above China"! Yes they really do need to seriously address the co2 emissions problem here.
For my little bit I collect all cardboard and waste paper, as well as any plastic bottles/cups/food containers etc. and leave it outside for the people to collect. At least they get a few quoi out of it and it goes to re-cycling.
I tend to shy away from buying to many plastic bottles and re-use them whenever possible; e.g buying potable water from the machine on the compound (much cheaper and environmentally friendly).
I amplify previous comments about using the subway and public transport as much as possible, as well as walking, re-useable bags and cutting down on water usage ... if everyone were to adopt these measures it would certainly go some way to reducing pollution.
Personally I will only use a taxi if absolutely necessary, I will do everything I can to find alternative transport as taxi's are not only environmentally unfriendly, but a complete rip-off - especially where foreigners are concerned!

Our rare car rides are to the airport with luggage or to the school an hour away. But our car is always full. It's amazing how Long I go without riding in a vehicle. I would have never thought it possible. The busses here are almost all electric now.

all the above are great ideas.  i especially have big shopping bags to carry my school items and use when i shop.  if you do no walk around in china and get involved in the street scene you miss out on about 90% of china.  it am not a fan of buses they are far too crowded.  however, i love subways and trains.  i think keeping your area clean and starting a small garden are good for the environment.  unfortunately the major problems with pollution in china you have no control over.  the little things do sometimes help alot though.

We sold our car this year and bought an electric car.  We do not drive much anyway we use the buses most of the time.  But remember China is where the US was about 40 or so years ago.  It will take some time for them to get things under control, but I think that they are going in the right direction.