I can understand the legislators in EU (who are undoubtedly in bed with European car makers) not wanting to update the Diesel tests because they knew the cars would not pass any updated, more 'real life' test regime. The Japs realised many years ago that Diesel engines were a 'dead end technology' that would never meet the tight emission standards that were on the horizon (especially in USA and Japan) and concentrated on Hybrid petrol cars. EU got miffed and banned Japs from the EU discussions (in about 2005 I think). Interestingly even Direct injection petrol engines emit Higher NOx than 'normal 'manifold injected petrol engines, but not as much a Diesels.
Remember when Bio-Diesel and Ethanol were going to save the planet, tropical countries were encouraged to grow palm oil, maize, soya and sugar cane - this meant the wholesale destruction of rainforest to make room for the 'bio-crops' - and all this while people in those very same countries were starving.
Next bandwagon seems to be plug in hybrid electric vehicles (PHEV) where because they can run on electric battery power for say 18miles (unless you want the heater on) they magically become exempt from VED, congestion charge etc. The fact that when engine is required they only do 30mpg is not taken into account, another fudge if ever I saw one.
The perilous state of our electrical supply in UK (because of fragmentation of generating companies and lack of investment, lack of leadership from successive governments, too much reliance on unreliable 'renewable wind and solar' ) where we have only 1 or 2 % spare capacity in winter means that if everyone plugs their electric car in to charge some parts of the country may suffer power cuts, To fit in with 'Carbon emission legislation' we are replacing coal with valuable gas to generate electricity at 40% efficiency where it can be burned at over 90% in domestic boilers to provide heat. All the while Germany and other countries are still building coal powered power station. Someone even thought it was a good idea to transport wood chippings all the way from Canada to replace British coal in power stations - madness on a grand scale.