Depends on what component of pollutant you're looking i.e. if
merely only on what your eyes can see coming out of the exhaust
pipes, then of course the diesel particulate emissions would be
more seenable than any emissions from a petrol vehicle. BUT one has
to gauge pollution on the overall point of view & from that
angle, visible & invisible pollutants considered, i don't find
any noticible difference between the latest diesel & petrol
vehicles in that overall both are equally 'damaging' to the
environment in their different ways.
I'll even not be surprised that the latest diesels have become even
'cleaner' than petrols, depending on what yardstick is used.
Overall the future of the diesel engined vehicle remains very
promising, so much so that even the top-class marques like
Mercedes-Benz continue to push very strongly in development &
sales of their diesel cars, vans etc. If diesel is really overall
'inferior' compared to petrols, i seriously doubt that such a
famous marque would have continued in more R&D & sales of
their diesels ! Afterall, they expected to value their reputation
much more than any other maker around.
