Remove a truck’s catalytic converter, install a ‘smoke switch’ that tricks the engine into burning more diesel than it needs, and before you know it you’re rolling coal, purging impenetrable clouds of soot through your exhaust pipe on I-10 in Texas, enough to repel the prig in the Prius riding your tail. Those of us who consider deliberate pollution a vice can forget that there are others who not only don’t care, but revel in it. But Donald Trump – who is today signing an executive order aimed at unravelling Barack Obama's climate legacy – hasn’t forgotten them.