Good so the car won't be killing people due to high noxious emissions.

Stick a petrol version of the engine in (Peugeot XU instead of XUD) and convert it to run on propane. There you go, now the exhaust is just water and carbon dioxide, and you don't die from breathing it in. No CO, no HC, and not really any more NOx that was in the air it sucked in.

This is why forklifts run on gas, instead of petrol or diesel.

We could have had incredibly clean air in our cities 25 years ago, if the government hadn't decided that pushing "scrappage schemes" to get people to buy "cleaner greener diesels" was cheaper.