If the government is not doing much, then volunteers can help by standing on street and observing passerbys, if someone spits or litters you can catch them red handed, ask them to pick up their trash and put it in dustbins, and educate them at the spot. Maybe you can hand them some brochures or give them some bags for spitting for free, and tell them the importance of keeping Shanghai and China clean.

When, a long time ago, I was in China, I went to eat in a nice restaurant, and even there I saw a man spitting on the polished floor. I was quite taken aback, but nobody ells seemed to be taking notice of it.
They told me this was a custom in China, better to spit something out then swallow it and get sick, so they explained to me. They even had special bowls for it to spit in called a spittoon, so I guess it is an old custom in the far east.

我在中国的时候，我去过一所好饭店吃饭。
在那儿我看到了一个人吐痰在饭店的抛光的地下。
我觉得作这样太不礼貌。一个中国人告诉我这是
中国古老的习惯。吐痰比吞咽好，以前他用痰盂
你可以吐在里面你的痰。

万事如意

陆蓝克

Before I visited Beijing, a friend made a comment to me. He said there were lots and lots of people in Beijing. If everyone spit all at once, it would be a lot of spit everywhere. When I came back, I told him that he was close. The difference was, it wasn’t everyone spitting, but many people spitting alot. Yes, and it was everywhere!