Major Differences between BS VI and BS VI Stage:These differences may be in fuel and in emission parameters. In fuel the extent of sulphur amount is the major difference in Bharat stage IV and Bharat Stage VI. The BS VI grade fuel contains 10 mg/kg(ppm) sulphur, while the BS IV grade fuel has 50 mg/kg(ppm).

The BS VI compliance will reduces the PM by 80% and NOx by 60% in diesel cars, while the NOx in petrol car by 25%. BS VI compliance has on-board diagnostics(OBD) mandatory for all vehicles. The OBD device informs efficiency of the systems in the vehicle. Compliance with BS-VI norms will require higher investment in technology to upgrade vehicles in stock and making new vehicles.