| For Two and Three Wheelers | |||
| Norm | Year of implementation | Technological improvement in the vehicle | |
| Two-stroke technology | four-stroke technology | ||
| Bharat Stage-I | 2000 | Intake exhaust, combustion optimization, | Four stroke engine technology |
| catalytic converter | |||
| Bharat Stage-II | 2005 | Secondary air injection catalytic convertor | Hot tube secondary air injection |
| For Four Wheelers | |||
| Norm | Year of implementation | Technological improvement in vehicle | |
| Bharat Stage-I | 2000 | O2 sensors- heated type and specially designed for super fast light off Introduction of close coupled catalyzers or maniverters in the exhaust system Introduction of electronic fuel injection system Change in catalytic loading | |
| Bharat Stage-II | 2001 | ||
| Bharat Stage-III | 2005 | ||