In Austria, smoking is still allowed in restaurants and it drove me insane. In old pubs, decades of cigarette smoke had imbedded itself into the building itself and I would struggle to breathe at times. Despite this, you can't say anything because... A: it's allowed. B: everyone smokes!! You simply have to put up with it.
Here in Asia, it is the same. The restaurants are often huge rooms so the smoke tends to disperse and there are often non-smoking areas such as the toilets and elevators. Consequently, I took the law into my own hands when a man decided to get into the elevator with a cigarette.
He was puffing away in a box full of cyclists, so when the door opened on the next level, I pushed him out. He turned and starting saying something in Chinese. I pointed at the no smoking sign as the elevator doors closed. I was very satisfied with myself.