The euro government set our exhaust emission levels, mot test checks the levels coming out of the exhaust, they often are not the adjustable at the time of test and the levels are set by the machine. Emission to high are usually a sign of several things i.e. faulty sensor, engine wear, and the way the car is driven. General servicing on a yearly base, keeping the engine in good order is the best prevention for the emission test, at NICE MOTORS we service and monitor the sensors on the engine which will reduce the emission levels. But from time to time the sensors do fail and therefore send the emission level to high, at NICE MOTORS we have diagnostic equipment to test the sensors and replace if required, therefore lowering the emission level.