BASF has announced that they will be raising the price of AdBlue by €45 per 1,000 liters. AdBlue is the 1/3 urea, 2/3 water solution used for the NOx after-treatment system in new diesel engines.

If you've seen bottles of AdBlue at filling stations and wonder what it's for and whether your car needs it, our guide will tell you everything you need to know. Picture the scene: you're in the queue ...