This kind of irritating statement most of us would have heard from NRIs and those who had been to foreign nations and have returned back.
Its in our hands. We obey the rules in foreign government. "You should not spit on the roads or you should not throw papers on the foot path" - if this has been written in other country, we obey it. But if it is written in India, we never care about it and sometime put garbage on the sign board itself that will hide the signs with the passage of time.
Say a person X who use to chew pan masala in India, stops it temporarily in other countries or spits it in the dustbin. But the moment he enters Indian airport, he is tempted to spit on the road side. He searches for dust bins to throw torn pieces of paper, but in India he throws them right under his feet and walks carelessly as if he is no longer connected with this world.
The moment Indian government brings a rule, the law breakers are busy in finding loop holes to escape from the rule.
Only if we start following these small practices, others will follow and practice it. Let us all join together to preserve the heritage of our nation.