BS4 vs BS6 – What Is the Difference Between BSIV & BSVI Engines?

What is BS4 (BSIV)?

BS4 stands for Bharat Stage 4, as per the Central Pollution Control Board. In 2010, the board released BS3, which BS4 followed in 2017. The standard controls in this version were much stricter than the older norms. The BS4 rules cover all the standard protocols needed for the vehicle, such as engine emission, governing body and electronic control unit.

One of the most significant changes in the BS4 model was the implementation of AHO, which stands for Automatic Headlight On. This was popularly applied to the two-wheelers and contributed significantly towards the safety measures.

What is BS6 (BSVI)?

After the implementation of BS4 in 2017, the board skipped the BS5 version. The BS6 version is meant to regulate the pollution emitted by vehicles. As per this version, there have been set levels of emissions permitted in a vehicle. This has been categorised differently for each type of vehicle for more accuracy.

If your vehicle emits pollution beyond these levels, you need to get your vehicle checked immediately. If the problem persists, you should consider changing your vehicle, as you might face legal complications. As per the Union Ministry of India, this change shall reduce the pollution levels of vehicles by 80-90%.

As per the Government of India, a mandated protocol is issued, which goes by the name Bharat Stage. These protocols were introduced to check vehicles and monitor their emissions effectively. It was implemented to keep a check on air pollution levels.

BS4 and BS6 Fuels: Key Differences

While understanding the BS4 vs. BS6 difference, a significant comparison can be made based on the engine and the fuel emissions of the vehicles. After the BS4, the Bharat Stage 5 was omitted, and the BS6 was introduced directly into the market. Here are the major BS4 vs BS6 differences in the engine and fuel emission.

Pollution Emission Norms (BS4 Vs. BS6):

After every few years, the board of Bharat Stage Emission Standards evaluates the existing version of norms that govern the aspects of a vehicle, such as their engine and fuel emission. Since these factors contribute significantly to the environment and ever-increasing pollution, certain steps are being taken to reduce these vehicles’ harmful emissions.

In 2017, as per the newer norms, the catalytic converter was added to the vehicles. This helped in reducing nitrogen-based emissions. In the next version, the BS6, carbon monoxide (CO) emissions from vehicles’ tailpipes were reduced as per this standard. So, vehicle owners must have a certificate from the pollution control unit to drive their vehicles. This certificate entitles vehicles to follow the BE6.

BSI, BSII, BSIII, BSIV, and BSVI: New Emission Norms

The new government-mandated BSI, BSII, BSIII, BSIV, and BSVI norms are guidelines issued to reduce vehicle emissions. Aimed at capping release of harmful gases from vehicle exhausts, details of these norms are shared below:

• BSI (Bharat Stage I): BSI was first introduced in 2000, and aimed at regulating vehicle emissions in India. Amid growing air pollution concerns, primarily carbon monoxide, hydrocarbons, and oxides of nitrogen emissions, it was the very first step ever taken in this nature.
• BSII (Bharat Stage II): BSII came a year later in 2001, aimed at strengthening the emission limits established in BSI. This phase mandated further reductions in harmful gases, raising the benchmark set at improving air quality and making it cleaner.
• BSIII (Bharat Stage III): BSIII came four (4) years later in 2005 and introduced even stricter limits on pollutants like sulphur dioxide and particulate matter, additionally mandating the use of better-quality fuels with lower sulphur content.
• BSIV (Bharat Stage IV):After a wait of twelve (12) long years, BSIV was rolled out in 2017 to significantly cut nitrogen oxides. Promoting the adoption of advanced technologies such as catalytic converters and diesel particulate filters in vehicles, it raised the bar further in reducing harmful emissions from vehicles.
• BSVI (Bharat Stage VI): In 2020, BSVI was launched straightaway skipping the BS-V stage. Considered the most stringent emission standard in India by far, it aligns closely with Euro 6 norms and enforces drastic reductions in NOx, sulphur dioxide, and particulate matter emissions. BSVI also introduced onboard diagnostics (OBD) and real driving emissions (RDE) testing to monitor compliance.

All of the above have played a crucial role over the years in reducing vehicular pollution, improving air quality, and fostering the development of cleaner and more sustainable technologies in the automotive industry.

List of BS6 Bikes/Two-Wheelers/Scooters Available in India 2024/2025

Check out the BS6 two-wheelers/bikes/scooters available in the Indian market now:

BS6 Bikes/Two-Wheelers:

BS6 Scooters

Conclusion

Now that you know the difference between BS4 and BS6 vehicles, it’s time to upgrade to the latest BS version bike. The latest BS version vehicles greatly contribute to the environment as they help control pollution levels. However, upgrading or buying a new two-wheeler will also impact your budget. So, why not get
bike finance from Muthoot Capital Services? They provide the best bike loan interest rates. With Muthoot Capital Services, you can easily pay off your bike’s value with lesser down payment options and monthly instalments.

FAQs About BS6 Vehicles

1. Among BS4 and BS6, what is the power difference?

In terms of power, the difference between BS4 and BS6 vehicles is as good as negligible. Norms for both focus on reducing emissions, and ignore engine performance. BS6 engines, though, may slightly reduce power output due to stricter emission controls.

2. Is BS6 more fuel-efficient than BS4?

In terms of fuel efficiency, BS6 vehicles are considered less fuel-efficient than BS4. Stricter emission norms require additional components like catalytic converters, slightlyly impacting fuel economy.

3. What is the full form of BS4?

Bharat Stage 4 is the full-form of BS4.

4. What is the full form of BS6?

Bharat Stage 6 is the full-form of BS6.

5. What’s next after BS6?

The next expected emission norm after BS6 in India is expected to be the BS7. BS7 is expected to further introduce stricter pollution controls and advanced emission technologies.

6. Why was BS5 skipped and BS6 launched directly?

BS5 was skipped and BS6 was launched directly by India after BS4 for a quicker transition towards cleaner and more advanced technologies. The move was made with the intention of aligning as fast as we could with global Euro 6 standards to combat severe air pollution.

7. Do BS4 vehicles require a pollution certificate?

Yes. It is mandatory for BS4 vehicles to have a Pollution Under Control (PUC) certificate, to ensure compliance with emission norms.