BS IV vs BS VI Emission Norms: A Comprehensive Guide

The Indian government has implemented the Bharat Stage Emission Standards (BSES) as a means to control the pollution generated by cars and two-wheelers. The BSES regulations are upgraded from time to time in tandem with advancing technology and changes in the environment.

Abiding by these standards is mandatory as per prevailing laws. At present, BS-VI emission norms have been made mandatory for all two- and four-wheelers that are manufactured, sold, and registered from 1st April 2020. Wondering what BS IV vs BS VI has to present, let us guide you.

Understanding BS IV and BS VI Emission Norms

Before we dive into the differences, let’s first get a clearer idea of each set of emission norms:

BS-IV Emission Norms

These norms came into effect in 2017 and were successors to BS2 and BS3 norms, which were introduced in 2005 and 2010, respectively. Some prominent changes introduced with BS-IV included tailpipe emissions, Electronic Control Unit (ECU), ignition control, and most importantly, Automatic Headlights On (AHO). The last one was especially relevant regarding the safety norms set by BS-IV.

BS-VI Emission Norms

The BS-VI was introduced in 2020 and was a substantial leap from BS-IV since it bypassed the fifth set of emission norms (BS-V). As per these norms, the permissible levels of different kinds of pollutants emitted by vehicles have been reduced considerably.

Note: Whether you have a car compliant with BS-IV or BS-VI emission norms, it is essential to ensure it with the right car insurance policy. While you may already have third-party insurance coverage, it may be a wise idea to opt for a comprehensive car insurance plan.

Also Read: Hyundai Aura Safety Rating | Global and Bharat NCAP Rating

BS IV vs BS VI Emission Norms: What are the Key Differences

Let’s consider the permissible emission levels first:

As can be seen from the above table, the difference between BS IV and BS VI permissible emission levels have been made stricter. Let’s understand this factor and BS IV vs BS VI.

1. Under the BS-IV emission norms, petrol motor vehicles could emit up to 80mg/km of Nitrogen Oxide (NO2). The BS6 emission norms, on the other hand, only allow up to 60mg/km. The PM or particulate matter emissions for petrol vehicles have also been set at 4.5mg/km under the BS-VI norms.

2. Diesel vehicles manufactured under the BS-VI regime will also have to comply with reduced NOx, PM, and HC+NOx emission levels.

3. BS-VI emission norms have also outlined newer regulations for the fuel used by the vehicle. As compared to BS4, the BS6 emissions norms have allowed for lower sulphur and NOx, two elements which are critical in petrol and diesel. To make up for the lubrication that is aided by sulphur, additives have been introduced to BS6-approved fuel to ensure the engine is properly lubricated.

4. Under the BS6 norms, Real Driving Emission has also been introduced to ensure real-time checking of the vehicle’s emissions. Another factor which came into force under BS6 norms and was absent under BS4 emission norms is the Onboard Diagnostic (OD).

5. Note that a BS6 vehicle would have to use BS6 fuel only to be able to meet the required levels. BS4 fuel would not suffice to meet the standards.

Also Read: Difference Between Comprehensive and Third-Party Insurance

How Can You Follow the Emission Norms in India?

Wondering how you can follow these BS4 and BS6 norms? Well, staying compliant with India’s vehicle emission rules is not complicated if you take a few practical steps. You must understand your vehicle’s standard, use the correct fuel, maintain it properly, and keep your documents updated.

Here is how you can make sure you fully comply with the norms:

Identify Your Vehicle’s Emission Standard

Firstly, confirm whether your vehicle meets BS4 or BS6 standards. You can check this by:

1. Inspecting compliance labels placed near the windshield, inside the bonnet area, or along the driver-side frame.

2. Reviewing your Registration Certificate (RC), which usually mentions the emission category under the vehicle model details.

3. Referring to Form 21 submitted during registration, where emission details appear alongside manufacturer information.

4. Checking the manufacturing year, vehicles registered from April 2020 onward follow BS6 norms nationwide.

5. Using the VIN (Vehicle Identification Number), the 17-character code reveals manufacturing details, including production period.

Keep Pollution Under Control (PUC) Valid

A valid PUC certificate proves that your vehicle operates within permitted pollution limits. To do this, make sure you:

1. Test your vehicle at authorised centres.

2. Renew the certificate before expiry.

3. Carry the updated record while driving.

Please note that driving without a valid PUC can attract penalties of up to ₹10,000.

Use the Correct Fuel Type

If you own a BS6-compliant vehicle, always refuel with ultra-low sulphur petrol or diesel. For instance, if you use an older-grade fuel, it can increase emissions, reduce engine efficiency, and violate regulatory standards.

Maintain Your Vehicle Regularly

Since routine servicing keeps emission levels under control, you should:

1. Replace air filters and engine oil on schedule.

2. Ensure sensors and emission-control components function properly.

3. Address warning lights immediately.

4. Avoid skipping manufacturer-recommended service intervals.

Adopt Responsible Driving Habits

Your driving style also influences your vehicle’s emissions. You can reduce pollution by:

1. Avoiding harsh acceleration.

2. Maintaining steady speeds.

3. Switching off the engine during long stops.

4. Keeping tyres properly inflated.

Ensure Proper Documentation and Insurance

Finally, along with emission compliance, maintain valid motor insurance and updated vehicle records. This will help you prevent another fine of up to ₹4,000.

Also Read: Difference Between Internal and External Combustion Engines

How Motor Insurance Complements Emission Compliance?

Following emission norms keeps your vehicle environmentally responsible, but motor insurance ensures it remains legally protected on the road.

Below are some of the pointers indicating its importance:

Supports Legal Road Use

Indian law mandates at least third-party motor insurance for every registered vehicle. Even if your vehicle meets BS4 or BS6 standards, you cannot legally drive it without valid insurance coverage.

Enables Smooth RTO Processes

Authorities often require active insurance proof during vehicle registration, ownership transfer, RC renewal, or permit applications. If your policy has expired, your application may face delays or rejection. Thus, valid insurance ensures uninterrupted administrative approvals.

Encourages Responsible Vehicle Maintenance

Comprehensive motor insurance policies often cover accidental damage, natural disasters, and other risks. When you maintain your vehicle properly for emission compliance, you also reduce the likelihood of breakdowns and claims. Thus, proper maintenance benefits both environmental performance and insurance risk assessment.

Promotes Overall Compliance

Meeting emission standards, maintaining a valid PUC certificate, and holding active insurance together demonstrate responsible vehicle ownership. All of these factors combined keep you road-legal, financially secure, and aligned with national environmental goals.

In short, emission compliance protects the environment, and motor insurance protects you. So, get comprehensive motor insurance policy from Bajaj General Insurance to drive with confidence and peace of mind!

Bottom Line

The transition from BS IV to BS VI marks a significant step toward reducing vehicular pollution and improving air quality in India. The stricter limits on NOx, particulate matter, and fuel composition highlight the government’s stronger environmental focus. Understanding BS IV vs BS VI helps vehicle owners make informed decisions about compliance, maintenance, fuel usage, and insurance, ensuring their vehicles remain both legally compliant and environmentally responsible.

Frequently Asked Questions

Can I still drive a BS IV vehicle in India?

Yes, you can drive a BS IV vehicle if authorities have not imposed local restrictions in your area. However, certain cities may limit the use of older vehicles during high pollution periods. Always check local regulations to stay compliant.

Does a BS VI vehicle offer better fuel efficiency than a BS IV vehicle?

In many cases, BS VI vehicles deliver improved combustion efficiency due to advanced engine technology. However, the actual mileage of your vehicle depends on driving habits, maintenance, and road conditions.

How does emission compliance affect motor insurance?

While emission standards do not directly determine premiums, insurers may consider risk factors during motor insurance policy pricing. Thus, maintaining your vehicle properly and abiding by emission norms can help you reduce premium prices over time.

Can a BS IV vehicle be upgraded to BS VI standards?

In practice, no. BS VI compliance requires major engine and emission-system redesign. Retrofitting is technically complex, extremely costly, and typically exceeds the vehicle’s economic value.

Do emission norms impact vehicle resale value?

Yes. Vehicles compliant with newer emission standards usually retain better resale value due to longer regulatory relevance and perceived technological advancement.

What happens if emission control systems malfunction?

Malfunctions may trigger warning lights, reduce performance, increase emissions, and potentially cause PUC test failures. Prompt diagnosis and repairs are essential to avoid compliance issues.

Disclaimer: The content on this page is generic and shared only for informational and explanatory purposes. It is based on several secondary sources on the internet and is subject to changes. Please consult an expert before making any related decisions.

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