Anti-pollution standards are becoming more demanding.
Commercial vehicles must meet such standards and for that reason, they shall
install the well-known “Anti-pollution
Systems”.
This article describes one of the most famous systems,
the SCR (Selected Catalytic Reduction), which was first used in commercial
vehicles to meet Euro 4 standards, coming into effect on October 1 2006. This
is the system that is still being used by most manufacturers in order to meet
Euro 6 anti-pollution standards, in force since 2014.