Since 1 April 2023, every new commercial vehicle sold in India has to meet BS6 Phase 2 emission norms. Phase 1 (April 2020) brought the big jump from BS4 to BS6; Phase 2 tightens how those limits are checked.
What changed in Phase 2
- Real Driving Emissions (RDE): emissions are measured on real roads, not only in a laboratory test cycle.
- OBD-II on-board diagnostics: the truck continuously monitors its emission system and warns the driver when something is wrong.
- Stricter monitoring of after-treatment: systems such as the DPF and SCR (which uses AdBlue / DEF) are watched more closely.
What it means for buyers
- Use genuine AdBlue (DEF). Most diesel BS6 trucks use SCR. Running without AdBlue, or with poor-quality fluid, can trigger warnings and limit engine power.
- Use BS6-grade diesel and the recommended engine oil. After-treatment parts are sensitive to fuel and oil quality.
- Do not ignore warning lamps. OBD-II will flag emission faults early; fixing them early is usually far cheaper.
- Budget for the technology. BS6 trucks cost more upfront than older BS4 models, but they are the only new trucks you can register today.
Buying a used truck?
Check the emission norm on the RC and the PUC certificate. A well-maintained BS6 truck with a clean service history is generally the safer long-term choice.
Tip: ask the dealer to show the after-treatment service records (DPF cleaning, AdBlue system checks) before you buy.
