This part of ISO 22241 describes best practice recommendations and requirements for handling, transportation and storage of NOx reduction agent AUS 32 (aqueous urea solution), specified in ISO 22241-1. These recommendations and requirements are necessary to preserve the specified quality of AUS 32 from any point of production to the point where it is filled into the onboard tank of the vehicle, in order to ensure the proper function of the selective catalytic reduction (SCR) converter systems.