BS7 Norms From April 1, 2029: 6 Major Changes Car Buyers Need to Know

Quick Read - The proposed BS7 norms will introduce stricter real-world emission testing, onboard pollution monitoring, brake and tyre emission limits, and minimum EV battery durability requirements in phases from April 2029 to 2035.

India’s proposed Bharat Stage VII (BS7) emission norms will introduce a broader framework for regulating passenger cars from April 1, 2029.

Unlike the transition to BS6, which brought significant reductions in several exhaust-emission limits, the BS7 proposal focuses heavily on stricter real-world emission testing, continuous pollution monitoring, battery durability and pollution from brakes and tyres. The requirements will be introduced in phases through 2035. The rules remain at the draft stage.

1. Real-World Emission Testing Will Become Stricter

One of the biggest proposed changes is a conformity factor of 1.0 for nitrogen oxides (NOx) and particle numbers in real-driving emissions tests from April 1, 2030. This removes the additional allowance over the applicable laboratory limits during these tests. Cars will have to demonstrate compliance not just under laboratory conditions but also during prescribed on-road testing, putting greater pressure on manufacturers to maintain emission-control performance in everyday driving.

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2. Cars Will Monitor Their Actual Pollution Levels

BS7 proposes onboard monitoring (OBM) systems alongside existing onboard diagnostics (OBD). While OBD identifies faults in emission-control equipment, OBM will monitor and record actual exhaust emissions, particularly NOx and particulate matter. The proposed system must detect emissions reaching at least 2.5 times the applicable limits.

This creates an additional layer of monitoring once a car is in use, rather than relying exclusively on periodic inspections and fault detection.

3. Brake and Tyre Pollution Will Come Under Regulation

BS7 will extend pollution controls beyond the exhaust pipe for the first time under this framework. From April 2031, passenger cars will face proposed brake-particle limits of 3 milligrams per kilometre for pure electric vehicles and 7 milligrams per kilometre for other specified powertrains, including petrol, diesel and hybrid cars.

From April 2035, a common brake-particle limit of 3 milligrams per kilometre is proposed across passenger-car powertrains. Tyre-abrasion requirements are also proposed from April 2031, although the numerical limits and certain technical requirements are yet to be specified.

4. EV Battery Durability Will Get Minimum Performance Requirements

Pure electric cars and plug-in hybrids will have to meet proposed minimum battery-capacity retention requirements. Batteries must retain at least 75% of their original energy capacity for up to five years or 1 lakh kilometres, whichever comes first. The minimum then becomes 67% for the period extending up to eight years or 1.6 lakh kilometres, whichever comes first.

These requirements introduce a defined battery-performance benchmark, rather than leaving battery durability entirely to manufacturer specifications. They should not, however, be confused with an automatic promise of free battery replacement.

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5. An Environmental Vehicle Passport Will Be Introduced

The proposed Environmental Vehicle Passport will provide buyers and owners with information about a vehicle's fuel consumption, pollutant emissions and traction-battery health. BS7 also introduces phased requirements for onboard fuel and energy consumption monitoring, with access to relevant vehicle data through diagnostic interfaces and, in later stages, wireless transmission.

The objective is to make vehicle efficiency and environmental performance more transparent throughout ownership.

6. Existing Exhaust Limits Will Not Simply Be Cut Across the Board

An important distinction is that the draft does not lower the principal passenger-car tailpipe limits for every pollutant. For example, the stated NOx limits remain 60 milligrams per kilometre for petrol cars and 80 milligrams per kilometre for diesel cars, while the particulate-matter limit remains 4.5 milligrams per kilometre.

The major changes instead concern how emissions are tested, monitored and controlled, alongside the introduction of brake and tyre pollution requirements and battery-durability standards.

BS7: Key Changes and Implementation Dates