Why Should You Buy BS6 Cars?

8 November
Why Should You Buy BS6 Cars?

BS6 cars and their guidelines were officially introduced in April 2020 as per a ruling by the Indian Supreme Court. These Bharat Stage VI (BS-VI) guidelines are the newest avatar following 2017’s BS4 guidelines. Introduced by the Bharat Stage Emission Standards (BSES), the new norms said that all cars manufactured after April 1, 2020, needed to follow the new BS-VI standards. This meant changes to the engine, changes in fuel, technological advancement etc. 

The goal of the new BS-VI standards was to reduce the environmental impact caused by the auto industry. With the air quality indices reaching the 200s in India, the need for pollution control is high. By creating new emission standards, the BSES is actively improving the AQI. Especially in the wake of COVID-19, where having good AQI matters more than ever before since the virus affects the respiratory system, introducing these new BS-VI standards is a step in the right direction. 

But what makes these new standards better than their predecessors, and why should you consider buying BS6cars? For that, we first need to understand what the BS4 standards entailed.


What the BS4 Emission Standards Meant


The first emission norms as put forth by the BSES emerged in 2000, with the name “India 2000”. BS2 and BS3 were introduced in 2005 and 2010, respectively, and BS-IV emerged in 2017. With each upgrade, the BSES tried to take the country’s emission norms closer to European standards of the engine and performance of the vehicles. Therefore, 2017’s BS-IV was far stricter than its predecessors. 

The regulations set down by the BSES included:

  • An Electronic Control Unit (ECU)
  • Ignition Control
  • Tailpipe Emissions Control
  • The AHO (Automatic Headlamp On)

These were among several other emission and safety standards that the regulatory body put down in 2017. By 2020, these standards felt insufficient in effectively curbing the worsening AQI. Therefore, the BSES released the BS-VI guidelines. 


Understanding the Differences Between the BS4 andBS6 Guidelines


When the BS-VI was introduced in 2020, it included a massive shift from the previous guidelines. These standards were far more comprehensive and forced innovation in the auto industry to meet the new demands. Filters and engines needed to be far more competent at minimising emissions and particulate matter. This is, however, only the tip of the iceberg.

  • For diesel vehicles, the BS-IV allowed 250mg/km of nitrogen oxide emissions. The HC+NOx emissions under BS-IV were even higher at 300mg/km. The BS-VI norms reduced both nitrogen oxides and HC+NOx to 80mg/km and 170mg/km, respectively.
  • The BS-IV regulations allowed a maximum of 80mg/km of nitrogen oxides and had no specific guideline about Particulate Matter. The BS-VI guidelines amended this, reducing NO2 emissions to 60mg/km and restricting PM in petrol vehicles to 4.5mg/km. 
  • The BS-VI norms introduced a Real Driving Emission (RDE) that monitored emissions in real-time. This way, the owner completely understood the impact their vehicle was making on the environment. Measuring the RDE involved attaching a Portable Emission Measuring System (PEMS) to the exhaust system of the car. After this, the vehicle is driven on the road under normal conditions and the PEMS records data. It is then connected to a computer which analyses the data and provides appropriate and accurate results. This was not included under the BS-IV norms. 
  • The BS-VI norms introduced a Selective Catalytic Reduction (SCR) and a Diesel Particulate Filter (DPF) to monitor and control emissions in BS-VI motor vehicles. The SCR includes a chamber where the catalyst is present, and the reaction happens. The specifications of the SCR and its chamber depend on the vehicle’s predicted operations. The cheaper chambers are made of vanadium and tungsten while the ideal catalyst is a zeolite catalyst which can sustain high temperatures while being affordable. This was not part of vehicles manufactured by BS-IV standards. 
  • The BS-VI norms mandated the use of an On-Board Diagnostic (OBD), which was not present under the BS-IV norms. The OBD monitors emission levels at the exhaust, helping the ECU notify you on your infotainment system if the functioning is not ideal. The technician may also connect the OBD inside the hood, making it only accessible to their computer, so they stay informed about the car's exhaust system. Therefore, they can better identify any problem areas.
  • The sulphur and nitrogen oxide in fuels, i.e. petrol and diesel, were also severely cut down through the new guidelines. The BS-IV guidelines allowed for 50ppm of sulphur in the fuel. The BS-VI fuel reduced this by five times, forcing petrol pumps to stock their tanks with fuel that only contained 10ppm of sulphur. This lack of sulphur – which aids lubrication in the engine – is compensated for through various additives. For nitrogen oxide, the permitted level under BS-IV was 70%, which has now been reduced to 25% under BS-VI.
  • While BS-VI fuel can be used in BS-IV vehicles, the reverse is not possible since BS-IV fuel does not adhere to the required emission standards. BS-IV fuel is no longer being manufactured although the complete transition from BS-IV to BS-VI vehicles can take up to 2035.


The Bottom Line about BS6 Vehicles


BS-VI compliant vehicles were introduced with purely as a humanitarian, environment-conscious move. These standards reflect the BSES’ work towards making the world a better place by reducing the amount of particulate matter and nitrogen oxides in the air. As we established early on, this directly contributes to improving the AQI. 

Both in petrol and diesel vehicles, the BS-VI exhaust emissions are far lower. They are 25% cleaner in petrol vehicles and 80% cleaner in diesel vehicles. This kind of improvement, especially in diesel vehicles which faced a lot of backlash when they entered the Indian market, is very noteworthy. 

Does this mean you should think about buying a BS-VI compliant diesel car?


Should You Consider Buying BS6-Compliant Diesel Cars?


The main complaint against diesel vehicles that made several major manufacturers such as Maruti, Volkswagon, Renault, etc. pull out of building them was the pollution levels. With the BS-VI norms, the cost of manufacturing these cars increased exponentially, further turning automakers off from making them.

But what do these norms mean for buyers? Is now a good time to invest in a BS-VI compliant diesel vehicle? The short answer: yes. Why?


Lower Pollution Levels


Diesel vehicles were always much more polluting than their petrol counterparts. The lack of comprehensive guidelines under the BS4 regime did not monitor emissions close enough. However, with the BS-VI vehicles, the fuel is far more controlled and emissions far cleaner. The many modifications that the new guidelines and standards brought are making modern-day diesel vehicles much more environment-friendly with far lower sulphur and nitrogen content. The addition of the OBD, SCR and DPF, in particular, help improve the quality and lower the environmental impact of diesel vehicles.


Diesel is More Useful in Big Motor Vehicles


Hatchbacks, smaller sedans, and other smaller vehicles no longer use diesel. However, bigger sedans and SUVs, which typically cost over Rs. 10 lakhs continue using diesel. Since a diesel engine offers more torque, it makes more sense for heavy SUVs like the Tata Harrier. Similarly, the diesel option of the MG Hector is far better than the petrol alternative. 


Diesel Offers Greater Efficiency


In terms of fuel prices, diesel outdoes petrol. As fuel prices continue increasing – as they have, especially since the BS-VI regulations – buyers need vehicles that use fuel efficiently. The Kia Seltos diesel model is a prime example of how efficiently a diesel-run engine uses its fuel. The Seltos delivers over 21kmpl on highways and 17kmpl in the city – far more than a petrol hatchback. The fact that a diesel vehicle can run for 650-700km on a full tank and go long distances with no stops are the cherries on top!


Diesel Vehicles are Better Today


Diesel vehicles got a bad reputation early on for being noisy, rough, and high maintenance. However, as new-age BS-VI diesel vehicles like the Kia Seltos are proving with their 1.5l capacity, diesel vehicles today are very quiet and smooth. In fact, the new BSES standards make diesel vehicles almost as quiet as their petrol peers.



Cheaper than Expected


The main prediction regarding the new BSES norms was that everything would be more expensive. While manufacturing costs and selling points have increased, the actual difference between diesel and petrol vehicles has substantially decreased. Taking the previous example of the Kia Seltos, it costs only Rs. 35,000 more than entry-level petrol and diesel models.

But why have we spent so long explaining the diesel vehicles? Simply because the impact that the diesel auto industry faced is the same as the industry on the whole. While we have outlined the improvements in the diesel vehicles post-BS-VI, these kinds of enhancements are industry-wide. After all, if the diesel vehicle can substantially reduce its environmental impact, it is unthinkable what these guidelines can do for other engines. 


The Two Main Fronts to Analyse the BS6 Guidelines


People choose cars based on several factors. The BS-VI guidelines just opened up another dimension for analysis: the environment. Therefore, this becomes the main front from which the BS-VI guidelines and vehicles following the guidelines can be analysed. The other front that we want to discuss is resale value. Here, you need to be more analytical and careful. Let us look at both of them closely.


Environmental Impact


The BS-VI guidelines ensure cars that are environmentally friendly by European standards. This is what the BSES was aiming for when formulating the guidelines and remains their achievement. Therefore, if you are primarily concerned about the environment but do not have the time for an electric vehicle, choosing a BS-VI compliant vehicle is your best option. The regulations and mandates that lower particulate matter and toxic nitrogen oxide emissions reduce your environmental impact drastically. 

While the vehicles may cost more and the servicing will be more expensive, if you think this is a small price to pay for cleaner air then buying a BS-VI compliant vehicle is a no-brainer. 


Resale Value


The other front, as we established, is the resale value. India’s used cars industry is booming as more people invest in second-hand vehicles now than ever before. Which then begs the question about BS-VI vehicles. What is the resale value for them?

Since BS-VI vehicles cost more, buying them short-term (5-6 years) and then selling them is sure to give you a fair price. Since the transition between BS-IV and BS-VI vehicles is set to continue until 2035, buying a BS-IV car long-term may seem like a smarter choice to cut costs. However, the BS-VI vehicle should still be preferable considering you can upgrade in a few years while still getting a lot of value for money. 




The BS-IV car continues being prominent in the Indian market due to how recent the guidelines were. Since vehicles are long-term investments, they are not projected to leave the market any time soon. Only once registration expires on every BS-IV car will they completely leave the market. However, for the sake of the environment and the air quality, investing in a BS-VI vehicle is a better idea. Especially with the trend of prices increasing everywhere, buying them now instead of later may be a better idea.

If you have questions or queries about which BS-VI vehicle will best suit your needs, you can contact Car N Drive, and we will be happy to help you! Our experts are well-versed in all the latest vehicles and technologies that will bring you the car BS-VI compliant car of your dreams!





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