Unethical driver

Petrol price is increasing and many people start to search alternative ways to save money.
So, some people choose diesel(or petrol with lead) who emits black smoke.
Do you think it is very unethical?

I understand the situation but can't they just save their money by less visits the cinema, less yam char with friends, or save water, save electricity so that they don't have a long bill list.
These black smoke will pollute the environment badly and also effects human health.
The global warming issue are becoming sever day by day.
They care only their wallet, not the environment they live in, not the earth their future generation going to stay!
Shame on them.

Those who driving the car may not notice the bad effects because the exhaust pipe is at the back of the car.
But the car behind them, e.g. me, will inhale the black smoke because of the bad air-cond and the black smoke will blur the front view.
I had this bad experience last week. I don't even dare to drive near to it.