BS-VII clock starts ticking as Centre sets 2029 target for emission norms

The government has proposed BS-VII emission norms from April 2029, introducing stricter real-world testing and brake and tyre pollution limits, while automakers seek more time to comply

The government has proposed introducing Bharat Stage VII (BS-VII) emission norms for passenger and commercial vehicles in phases beginning April 2029, bringing pollution from brakes and tyres, tougher real-world emission checks, onboard monitoring and battery durability under a wider regulatory framework. Automobile manufacturers have flagged concerns over the timelines, warning that the transition could disrupt product-launch plans and divert engineering resources from electric vehicle (EV) development.

 

Three draft notifications issued by the Ministry of Road Transport and Highways (MoRTH), published in the Gazette on October 13, prescribe different implementation dates for vehicle categories. BS-VII standards are proposed from April 1, 2029, for M1-category passenger vehicles, including cars and SUVs; April 1, 2030, for N1-category light commercial vehicles with a maximum permissible mass of 3.5 tonnes; and April 1, 2031, for buses and heavier commercial vehicles falling under the M2, M3, N2 and N3 categories.

  

The regulations would be introduced in stages through April 2035, with different deadlines for emission testing, brake particle limits, tyre abrasion, onboard monitoring and battery performance.

 

Unlike the transition from BS-IV to BS-VI, the proposed BS-VII norms for passenger cars do not lower the principal tailpipe emission limits for carbon monoxide, nitrogen oxides (NOx), hydrocarbons and exhaust particulate matter. For instance, the NOx limits remain at 60 milligrams per kilometre for petrol vehicles and 80 milligrams for diesel vehicles, while the particulate matter limit remains 4.5 milligrams per kilometre.

 

The more significant changes lie in how emissions are measured under real driving conditions, monitored during a vehicle's operating life and controlled beyond the exhaust system.

 

For buses and heavier commercial vehicles, the proposed emission limits are measured per kilowatt-hour rather than per kilometre. The draft specifies a NOx limit of 200 milligrams per kilowatt-hour under prescribed laboratory test cycles and 260 milligrams under real-driving emissions testing. It also specifies limits for particulate matter, particle numbers, carbon monoxide, ammonia, methane, nitrous oxide and other pollutants.

Brakes and tyres brought under regulation

A significant change under BS-VII is the introduction of limits on particles released through brake wear, along with requirements to address tyre abrasion. These emissions occur even in vehicles without conventional engines.

 

For passenger vehicles, brake particulate matter (PM10) limits would apply from April 2031, with a ceiling of 3 milligrams per kilometre for pure EVs and 7 milligrams for other specified powertrains, including conventional engine vehicles and hybrids. From April 2035, a uniform limit of 3 milligrams per kilometre is proposed.

 

For N1 light commercial vehicles, brake emission limits would apply from April 2032, with different thresholds according to vehicle class and powertrain. For the heavier N1 Class III vehicles, the proposed limits are 5 mg/km for pure EVs and 11 mg/km for other specified powertrains.

 

Buses and heavier trucks would face brake particle emission requirements from April 2033, although the numerical limits for these categories are yet to be notified.

 

Tyre abrasion requirements are proposed from April 2031 for passenger vehicles, April 2032 for light commercial vehicles and April 2035 for heavier commercial vehicles. The numerical limits and certain testing procedures are to be notified separately.

Tougher testing and monitoring

The draft norms also expand requirements for real-driving emissions testing, which measures pollution while vehicles are driven on roads rather than only in laboratories.

 

For passenger vehicles, the proposed conformity factor of 1.0 for NOx and particle numbers in type-approval real-driving emissions testing from April 2030 would remove the additional allowance over the applicable laboratory limits during such tests.

 

The framework also introduces onboard monitoring (OBM), supplementing existing onboard diagnostics systems. While diagnostics identify faults in emission-control equipment, OBM is intended to monitor actual emissions during vehicle operation.

 

The draft notifications provide for phased implementation of onboard fuel and energy consumption monitoring, including provisions for wireless access to certain data. An Environmental Vehicle Passport would make information on emissions, fuel consumption and battery health available to users.

 

For passenger EVs and plug-in hybrids, the draft proposes minimum battery energy performance retention of 75 percent for up to five years or 100,000 km, whichever comes first, and 67 percent for the subsequent period up to eight years or 160,000 km.

 

The N1 draft also specifies battery durability requirements, while numerical thresholds for the heavier commercial vehicle categories are to be notified separately.

Industry seeks more time

The proposed April 2029 deadline for passenger vehicles has caught manufacturers by surprise, with industry sources arguing that a 2032 timeline would be more pragmatic given the scale of technological changes, investments and testing capacity required.

 

A senior official at a passenger vehicle manufacturer said the biggest concern was the potential disruption to EV development. With internal combustion engine vehicles accounting for nearly 90 percent of manufacturers' portfolios, companies would have to prioritise upgrading existing models, leaving limited engineering manpower and research resources for new electric models.

 

The official said automakers could be forced to revisit product-launch pipelines between 2027 and 2030, potentially going back to the drawing board on some planned launches.

 

“The timeline is ambitious, but not impossible. The immediate priority should be to finalise the rules and testing protocols, as the industry has roughly 30 months to prepare for challenges that go well beyond engine upgrades to include testing capacity, software, monitoring and battery durability,” said Ravi Bhatia, president, JATO Dynamics, commenting on the passenger vehicle proposal.

 

“The phased introduction of brake and tyre requirements eases the burden, but inconsistencies in implementation dates and lack of clarity on certain limits and technical specifications need to be addressed. The real measure of preparedness will be the time available between the finalisation of unambiguous standards and mandatory compliance. Any delay would compress development and validation timelines, pushing up costs, particularly for lower-volume, price-sensitive models,” he added.

 

On the implications for smaller cars, the senior OEM official said high-volume models such as the Maruti Suzuki WagonR, Hyundai Venue and Tata Punch remained important to manufacturers, making it necessary to upgrade vehicles across their portfolios rather than simply discontinue them.

 

Bhatia said, “Much will depend on the cost of compliance. Small cars are particularly price-sensitive, while diesel buyers are more concerned with total cost of ownership and performance. Buyers in the high-end luxury segment may be better placed to absorb the additional costs.”

 

However, higher compliance costs for conventional vehicles could also accelerate the shift towards EVs by narrowing the price differential between the two technologies.

 

Sunil Dahiya, founder and lead analyst at Envirocatalysts, said investments in cleaner combustion technologies could bring the costs of conventional vehicles closer to those of EVs, potentially prompting some manufacturers to shift entirely towards electric production in certain vehicle categories.

 

He said stricter standards for conventional vehicles would nevertheless remain necessary because charging infrastructure would not expand uniformly across India.

 

“Upgrading fossil-fuel emission standards gives Indian consumers the freedom to choose between EVs and cleaner traditional powertrains. Establishing stricter, modern standards ensures that fossil-fuel vehicles operating on our roads remain as environmentally accountable as possible during this energy transition,” Dahiya said.

 

The ministry has invited objections and suggestions on the draft rules within 30 days.