These substances can generate air pollution particles.
Free public transport could be one way to get more people to ditch the car.
Researchers funded by VW, Daimler and BMW are accused of testing diesel fumes on monkeys and humans.
Time's up for the internal combustion engine.
The great dream of cars running on sustainable petrol has not bitten the dust. Here's why.
The road to an electric future needs to be paved with more than good intentions.
Diesel engines have been demonised for their emissions but the technology has already cleaned up its act.
But the most effective measures will be unpopular.
It's about time Europe ditched the diesels – so what are the alternatives?
Raging debates about the state of South Africa's energy industry have missed one critical area, the role of transport fuels and base chemicals.
Diesels typically have good fuel economy, but hot on the heels of the Volkswagen affair, Australia is set to tighten the rules for diesel car emissions - which will put a dent in engine performance.
Volkswagen and others may have been hamstrung by a low opinion of indifferent car buyers.
Computers control much of an engine's performance these days. And it's surprisingly easy to tweak the software to bypass emissions controls, as done by Volkswagen.
The VW emissions scandal is an opportunity to forge ahead with fuel cell technology for cars.
It's likely that many people knew Volkswagen was cheating on emissions tests, including the engineers who built the 'defeat device'. But why did no-one at the car maker blow the whistle?
Volkswagen's emissions cheat didn't just anger owners and regulators; the cost to human health from violating air quality rules exceeds US$100 million.
Can VW rebuild public trust? Its survival may depend on repairing the image damage caused by deception over clean diesels.
The market reaction to the VW emissions scandal is just like that of a jilted lover.
Current clean diesel technology is more than capable of meeting tough air quality rules while still delivering excellent fuel performance. Biofuels could make it even cleaner.
Volkswagen's cheating allowed its vehicles to pass rigorous emissions testing, giving customers maximum driving performance at the cost of the environment and our health.