I wasn't in the mood to troll now. But as soon as you mentioned firewall, i know you're simply butthurt.
To answer your question, I've been on Chinese and Indian trains. Have you?
I've never seen this on Chinese trains but its an everyday issue in Indian trains.
I have been on Chinese HSR and they are pretty clean, as you d expect with any brand new public transport. But the normal Chinese trains seem to be another story.
And you still didn't answer as to why civilized Chinese on "Rare occasions" decide to turn the train carriages into garbage dumps?