The SCR NOx control is another term for selective catalytic reduction (SCR) is a new high-tech technology that can drastically reduce nitrit oxide (NOx) emissions in diesel engine. Its primary function is to change harmful NOx outputs into safe nitrogen and water vapor, thereby greatly reducing air pollution. This method also destroys NOx with a liquid-reductant agent. This agent--often urea--comes from a tank that the device is mounted above, such as one might find in a locomotive engine's untended rear compartment for example; it may even be located at an off-road vehicle's rear end. SCR systems are equipped with monitoring sensors and a control unit that continuously keeps an eye on the process of converting NOx into N2 and water vapor for maximum efficiency. SCR NOx control systems are widely applied from heavy vehicles like trucks and buses. to industrial machines, power generation plants. They all receive the benefit of meeting emissions laws with greatly reduced environmental impact.