See, the problem is that you are savages, no offense.
Of course smoking in public offices must be restricted by the government, which represent the voters and which in turn are elected to govern the State.
The public cannot harm the health of the citizens that it has to protect by mandate.
If you wanna smoke and harm yourself (I am a smoker myself) do it on private property, away from people that have to be there for reasons beyond their will (for example testify at a trial).
Of course the government is the solely ultimate responsible of controlling (i.e. banning for some uses) hard drugs.
Who would you put in charge of it?
Of course it has to control guns, you can't let it control to private entities that profit from arms, it would be crazy!
You would see kids that go to school and shoot other kids.
Lucky us nobody in the World has ever thought of not strictly controlling guns!
That would be a nightmare!
Of course it is the only one who can ban diesel cars from cities and all of the above, you need laws to make it happen, the parliament writes and approves them, it's government's duty to enforce them.
Government is not the enemy, government is the average of public opinion that becomes ruling class for a brief period of time depending on how many votes that coalition of ideas and (of course) interests can get from the citizens.
The idea that the government is formed by aliens who come from another galaxy to ruin our otherwise beautiful peace and harmony is idiotic at best.