The government has proposed introducing Bharat Stage-VII (BS-VII) emission norms for passenger vehicles (PVs) from April 1, 2029, bringing brake and tyre pollution, tougher real-world emissions checks, and battery durability under a wider regulatory framework.
The proposal caught automakers by surprise. Industry executives warned that the compressed timeline could disrupt product launch schedules and slow electric vehicle (EV) development as companies divert engineering and research resources towards compliance.
The Ministry of Road Transport and Highways (MoRTH), in a draft notification dated October 12, has proposed implementing the standards in three phases — April 2029, April 2031, and April 2035. It primarily covers M1-category PVs, including cars and sport utility vehicles with no more than eight seats in addition to the driver’s seat. Industry sources expect subsequent notifications covering light, medium and heavy commercial vehicles.
Unlike the transition from BS-IV to BS-VI, the proposed BS-VII framework does not lower the principal tailpipe emission limits for PVs. Limits for carbon monoxide, nitrogen oxides (NOx), hydrocarbons, and exhaust particulate matter (PM) remain unchanged. For instance, the NOx limits remain at 60 milligrams per kilometre (mg/km) for petrol vehicles and 80 mg/km for diesel vehicles, while the PM limit remains at 4.5 mg/km.
The key changes concern how emissions are tested and monitored throughout a vehicle’s life, alongside new requirements for brake and tyre pollution, EV battery performance, and vehicle data.
Industry executives said the proposed standards would nevertheless require heavy investment in technology, software, testing facilities, and engineering capabilities.
Launch schedules may be disrupted: Industry
Automakers have argued that a 2032 deadline would be more pragmatic than April 2029, given the scale of preparations required. Industry sources said manufacturers already had product development programmes and investment plans extending into the next decade, and the proposed transition could force them to revisit launch schedules between 2027 and 2030.
A senior executive at a PV manufacturer said the biggest concern was the potential impact on EV development.
With internal combustion engine (ICE) vehicles accounting for nearly 90 per cent of manufacturers’ portfolios, companies would have to prioritise upgrading existing models to meet BS-VII requirements.
This could leave limited engineering manpower, research and development resources, and testing capacity for developing new electric models.
The official said manufacturers could be forced to revisit plans for some launches. Industry representatives favour a phased transition beginning in 2032.
Brakes, tyres to be tested
One of the biggest changes under BS-VII is the explicit regulation of pollution from brakes and tyres, which generate particulate emissions even in vehicles without tailpipes.
From April 1, 2031, the proposed limit for brake particulate matter (PM10) will be 3 mg/km for pure EVs and 7 mg/km for conventional engine vehicles, hybrids, and other specified powertrains.
From April 2035, a uniform limit of 3 mg/km will apply to all M1 vehicles.
EVs could benefit from regenerative braking, which reduces reliance on conventional friction brakes, but would still have to comply with the prescribed limits.
Tyre abrasion requirements are also proposed from April 2031. However, the numerical limits and detailed testing procedures are yet to be notified, leaving manufacturers uncertain about the technical changes and costs involved.
Lab tests not enough
The draft also tightens requirements for real-driving emissions testing, which measures pollution using portable equipment while vehicles are driven on roads.
Although BS-VI already mandates real-world testing, the proposed BS-VII framework specifies a conformity factor of 1.0 for NOx and particle numbers for type approval from April 1, 2030.
So, vehicles would not be allowed an additional emissions margin over the prescribed laboratory limits during the applicable real-world test.
An executive at a Mumbai-based automaker said the change could require manufacturers to improve emission control systems and ensure they perform consistently under everyday driving conditions.
The draft also expands onboard emissions monitoring once vehicles enter service.
While BS-VI requires onboard diagnostics (OBD) to detect faults in emission-control systems, BS-VII introduces on-board monitoring to measure and record actual NOx and particulate emissions.
The draft requires the system to detect emissions reaching at least 2.5x the applicable limits.
From April 2032, monitoring data must also be accessible through the vehicle’s OBD port, according to the draft.
