AN increasing number of petrol stations have extra tanks to forecourts – but do you know what they're for?
Sitting next to diesel and petrol, the blue pumps shouldn't be confused for another type of fuel.
What is AdBlue?
It's actually AdBlue – a urine-based solution used in diesel cars to slash emissions by converting dangerous nitrogen oxide into water vapour and nitrogen.
But many drivers are unaware they even need it in their cars because it's normally topped up as part of a regular annual service.
However, latest reports suggest high-mileage drivers are churning the solution quicker and are having to fill it up themselves.
Mercedes even came underfire for potentially switching off the tech in emissions tests to try and make tanks last longer.
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