An article regarding diesel vehicles, primarily Toyota, failing to meet emission standards with drivers being treatened with fines.
And another article claiming some new vehicles actually emit less than the manufacturers’ state.
And an article from 04.04.2018 regarding the AAA warning that tighter emission standards would increase vehicle prices and affect household budgets, in stark contrast to their claims in the top article that they have been supportive of tighter emissions standards for years.
Personally. I have never seen a diesel vehicle blowing white smoke but I have seen many blowing black smoke as they accelerate, presumably due to dirty injectors.