
Stage I: we reduced Nitrogen Oxide (NOx) emissions from diesel machines
Stage II: we focused on reducing NOx, Hydrocarbons (HC) and Particulate Matter (PM)
Stage III: we achieved a major reduction of PM and a further reduction of NOx
Stage IV: we have reduced NOx levels dramatically and have further reduced PM again.

The following table shows the magnitude of the reduction of emission levels from Stage I to the current Stage IV:
| Engine output P | CO | HC | NOx | PM |
| 56 ≤ P ≤ 130 kW | in g/kWh | |||
| Stage I (1999) | 5.0 | 1.3 | 9.2 | 0.70 |
| Stage IV (2004) | 5.0 | 0.19 | 0.4 | 0.025 |
| Emission reduction (in %) from Stage I to Stage IV |
0% | -58% | -96% | -96% |