Clearing the Air: BS6 & BS 6.2 Emissions Norms Explained

Here’s everything you need to know about BS6 and BS6.2 emissions norms in India

India has transitioned to the BS6 emissions standards, skipping the BS5 regulations, as a giant move towards cleaner air. Let’s know all about the latest emissions standards and how they have proved to be one of India's most significant technological leaps.

What are BS6 Emissions Standards?

Bharat Stage is the emissions standard regulated by the Central Pollution Control Board, which works under the Ministry of Environment, Forest, and Climate Change. The term BS4 or BS6 defines a maximum permissible pollutant limit emitted by a vehicle's exhaust. The critical difference lies in how strict the pollutant limits are.

These standards, first introduced in 2000, are based on European regulations and have continuously been rolled out with updated norms every few years.

The second (BS2) and third (BS3) standards came into effect in 2005 and 2010, respectively, followed by BS4 standards in 2017. 

The BS4 to BS6 transition was the quickest of the lot, with the latter coming into effect in April 2020. 

Skipping the BS5 regulations is considered a substantial leap, as BS6 aligns with the Euro 6 regulations being followed in most European countries.

Changes Brought by BS6 Norms

The transition from BS4 to BS6 was challenging, as it skipped the BS5 emissions standards. 

With the new regulations in effect, the auto manufacturers had to calibrate the engines and improve the fuel injection system and cylinder pressure after treating NOx (Nitrogen Oxide) and PM (Particulate Matter).

Once this was achieved, it resulted in reduced carbon emissions. And while the updated technology rendered the engines slightly less powerful, on the positive side, the vehicles began to achieve improved fuel economy figures. For 2-wheeler owners, the updated emissions standards addressed the core issue of rising fuel prices.

The alterations are not limited to emissions levels but also affect fuel dispensation. This means all petrol pumps were dispensing BS6 fuel from April 1, 2020. However, that wasn’t a cause of concern for BS4 vehicles, as BS6 fuel is compatible with BS4 vehicles. 

The only change needed was the lubrication, as the permissible sulphur level, which plays a crucial role in engine lubrication, had been reduced. By using certain lubricants, BS4 vehicles were running smoothly.

The new norms are especially critical for two-wheelers as they get onboard diagnostics (OBD) for the first time, compared to four-wheelers, which brought this technology decades ago. 

The OBD is a computer system that monitors a vehicle’s operation and receives data from various sensors to ensure proper functioning. The system lets service technicians get detailed information about any malfunctions.

Impact of BS6 Norms on the 2-Wheeler Industry

As the manufacturers replaced affordable carburettors with expensive fuel injection systems, the price of 2-wheelers increased by 10-15 per cent, resulting in a drop in sales. Post COVID-19, the manufacturers and the auto industry caught pace with the latest standards and recovered from the slump. 

In April 2023, phase 2 of the BS6 emission standards, known as BS6 RDE or BS 6.2, was introduced with several fundamental changes.

What’s New in BS6 Phase 2 (BS6.2) Emission Standards?

The new norms were even stricter than the previous ones, emphasising further reducing harmful vehicle carbon emissions. Here are the key aspects of BS 6.2 emission standards:

Stricter Emission Limits: The second phase of BS6 further restricts permissible levels of pollutants by a significant margin. The new norms focus on reducing Particulate Matter (PM) by 80 per cent, Nitrogen Oxide (NOx) by 68 per cent and Carbon Monoxide by 50 per cent.

Introduction of RDE (Real Driving Emissions) Test: Phase 2 introduces the RDE test, which evaluates the actual emissions during real-world on-road driving, in addition to laboratory testing brought in Phase 1. The RDE aims to check the real-time emission levels based on driving style, traffic conditions, and varying speeds.

Advanced OBD-2 Systems: Phase 2 also updates the existing onboard diagnostic (OBD) system to monitor oxygen sensors, catalytic converters, and engine misfires closely. Where oxygen sensors monitor the oxygen levels, the catalytic converter reduces the level of harmful emission, triggering warning lights if the set parameters are exceeded.

Impact of BS6 Phase 2 Emissions Standards

The transition from BS4 to BS6 was challenging for manufacturers, as they had to bear the brunt of the technological advancements needed for the changeover. However, the move from BS6 Phase 1 to Phase 2 wasn't very noteworthy.

That said, 2-wheelers with the new standards still demand a premium of Rs 2,000-10,000 over their previous versions.

Bottom Line

Vehicular emissions are a big environmental concern that needs the utmost attention. Though the transition to the BS6 regulations has created some adaptive challenges for manufacturers and consumers alike, they are meant to benefit all of us in the long run.

Implementing these emissions standards has helped improve air quality, public health and overall well-being. Further, the latest norms align us with the global benchmarks, which are crucial to facilitate the import and export of advanced technology and international collaboration.