Last month’s supreme court ruling forcing the Government to act on air quality targets is likely to lead to more low emission zones (LEZs) and congestion charging schemes.

This will be a game-changer for fleets. Environmental tax incentives are decisively shifting away from greenhouse gases towards air quality agents like particulates and oxides of nitrogen (NOx). Low CO2 levels are still important, of course. But when it comes to future-proofing fleet policies, the numbers in question will be the ones in the Euro series of exhaust emissions standards.

Euro 6 will be introduced on all first registration cars and on vans type approved from September 1, 2015 and all light commercial vehicles registered from September 1, 2016, and is likely to set the standard for cleanliness when UK cities start to impose entry restrictions as a result of the court ruling. Technologically, Euro 6 is a step change up from Euro 5 as virtually all Euro 6-compliant diesel cars and vans will incorporate the AdBlue exhaust treatment system in order to meet its tough limit on NOx emissions.

AdBlue is not new – buses and heavy trucks have been using it for several years. It is a compound of CO2 and ammonia dissolved in purified water. When AdBlue is injected into diesel exhausts, it neutralises most of the NOx emissions. It’s not expensive, costing £1-£1.50 per 1,000 miles in cars. Most new diesel cars will be able to carry enough AdBlue to last between scheduled services, while vans, which use more, will need to be topped up regularly by drivers or depot staff.

Essentially, it is like brake fluid or engine oil. Users need to make sure the right stuff goes in the right place and keep an eye on any dashboard warnings.

More importantly, the arrival of leaner, cleaner Euro 6 diesels is good news for car and van fleets, which have long benefited from diesel vehicles’ flexible power delivery and strong wholelife costs, due to CO2 tax efficiency and frugal fuel consumption. These benefits should be reason enough to embrace the next generation of fleet diesels wholeheartedly from now on.