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 aimed to set a uniform standard for the pollution emitted by vehicles on the roads. They 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. Along with it, a Car insurance policy with at least third-party coverage is also mandatory for cars to be driven on roads. 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. Earlier, BS-IV standards were the norm. Wondering what each emission norm means and what the differences between them are? 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 insure 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. Along with third-party coverage, a host of other events and risks are also covered under a comprehensive plan.  Claims are subject to terms and conditions set forth under motor insurance policy. *

Differences Between BS-IV and BS-VI Emission Norms 

Let’s consider the permissible emission levels first:

Fuel type	Pollutant gases	BS-IV	BS-VI
Petrol vehicles	Nitrogen Oxide (NOx) limit	<80mg>	<60mg>
	Particulate Matter (PM) limit	-	<4.5mg/km
Diesel vehicles	Nitrogen Oxide (NOx) limit	<250mg>	<80mg>
	Particulate Matter (PM) limit	<25mg>	<4.5mg/km
	HC + NOx	<300mg>	<170mg/km

As can be seen from the above table, the permissible emission levels under BS-VI have been made stricter. Let’s understand this factor and other differences in detail:

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 lesser 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.

By now, you may have a clear understanding of BS4 and BS6 emission norms and the differences between both. However, abiding by these norms is not the only way to ensure your car is safe and compliant with mandatory laws. Another important aspect of the process is to have the right car insurance policy.

Importance of Having a Car Insurance Policy

As per the Motor Vehicles Act of 1988, any car owner should have a third-party insurance policy. In case of an accident that causes damage to a third party, such a policy can be of immense help. However, it may not be useful if your car were to suffer damages in an accident or other situations. Comprehensive policies are better suited in these cases. Since they offer own-damage cover and the added benefit of optional add-ons, it provides extensive protection. Claims are subject to terms and conditions set forth under motor insurance policy. * To get a quote for a comprehensive car insurance plan, you can use online tools such as the car insurance premium calculator. Reaching out to a finance professional or a car insurance agent may help you in getting a deeper understanding of the matter.   * Standard T&C apply. Insurance is the subject matter of solicitation. For more details on benefits, exclusions, limitations, terms, and conditions, please read the sales brochure/policy wording carefully before concluding a sale.