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HomeFeatured ArticlesGoMechanic InformativeBS6 (Bharat Stage 6) | Explained

BS6 (Bharat Stage 6) | Explained

Before going in-depth into the BS6 or Bharat Stage 6 norm, let’s start with the basics. The Bharat Stage Emissions Standards (BSES) was introduced in the year 2000 are automotive emissions standards mandated by the government of India to keep a check on air pollutants from an internal combustion engine in a vehicle. These standards are set by the Central Pollution Control Board under the Ministry of Environment and Climate change.

Watch this detailed video on 8 most important questions on BS6 (Bharat Stage 6) emission norm in India:

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Update [October 2018] In a recent ruling, The Supreme Court has ruled that BS4 vehicles will not be sold after March of 2020 when the BS6 norms are put in place.

BS 6 Compliant Toyota Yaris Launch Soon

The BS (Bharat Stage) norms are based on EURO (European) emissions standards. The “India 2000” was rolled out in the year 2000, followed by BS2 and BS3 in 2001 and 2005 respectively. It wasn’t until BS4 (4th stage) (BSIV), that more stringent emissions mandates were enforced. In 2016, the government of India decided to skip BS5 altogether and implement Bharat Stage 6 (BS 6) by the year 2020.

What is BS6 (Bharat Stage 6)?

The Bharat Stage 6 (BSVI) norm is the sixth mandate for vehicular emissions and a much welcome change amidst the rampant air pollution in India. BS 6 is a stricter, more restrictive norm that will give a jumpstart to India’s long battle with air pollution. With the roll-out of the BS 6 norms, India will come at par with the US and European equivalent emissions norms.

Latest: Tata Nexon BS6 Variant Spotted

Update [April 2019] Maruti Suzuki India Ltd (MSIL) chairman R.C. Bhargava has announced that it will cease production of all diesel cars by April 2020.
Update [September 2019] Maruti Suzuki has upgraded its current line-up of vehicles with as much as 8 BS6 equipped petrol-powered. These include the WagonR, Ertiga, Dzire, XL6, Swift, Baleno and the recently launched S.Presso.
Update [October 2019] Maruti Suzuki Sells Over 2 Lakh BS6 Vehicles In 6 Months

Exclusive: Over 2,00,000 BS 6 Cars Sold: Maruti Suzuki

When will BS6 come to India?

BS6 or Bharat Stage 6 emission norm is due to arrive in India by 1st April of 2020.

How is BS6 different from BS4?

  1. The norm will bring a change in the fuel, as the BS6 compliant engine require BS6 fuel. A BS6 vehicle using BS4 fuel will not adhere to the BS6 norms. Indian oil companies have already started distributing BS6-grade Petrol and Diesel at 391 filling stations in Delhi with plans to make BS6 fuel available in all 13 major metro cities by April 2019.
  2. A vital difference between BS6 and the outgoing BS4 fuel is that the BS6 fuel contains 5 times fewer sulphur traces (10 parts per million) compared to BS4 (50 ppm). NOx (Nitrogen Oxide) level will be brought down by a staggering 70% for Diesel engine and 25% for Petrol Engines.
  3. The BS6 brings along a plethora of changes, most significant being the mandatory OBD (Onboard Diagnostics) for all vehicles.
  4. RDE (Real Driving Emission) will be introduced for the first time that will measure the vehicle’s emission in real-world conditions against simulated conditions.
  5. Introduction of DPF (Diesel Particulate Filter) and SCR (Selective Catalytic Reduction) for Diesel engines.

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What is a BS6 ready engine?

A Bharat Stage 6 ready engine has major modifications to its components to make it cleaner and adhere to the BS6 emission norm. Modifications like improved fuel quality composition and a DPF (Diesel Particulate Filter) and SCR (Selective Catalytic Reduction) in diesel cars are put to use to make the vehicle BS6 ready.

Also Read: Mahindra Bolero Power+ | India’s First BS6 Ready SUV

India’s passenger vehicle giant, Maruti Suzuki has updated its current line-up with 8 new BS6 ready petrol engine equipped cars. Even luxury car manufacturer viz. Mercedes Benz is now offering the Mercedes Benz C Class, Mercedes Benz E Class and the Mercedes Benz V class to upcoming BS6 norms.

What are the challenges with BS6?

While it all sounds good to the consumers, it isn’t all hunky-dory with car manufacturers. With the eventual phase-out of BS4 and introduction of BS6, automakers are pressing round-the-clock to develop BS6 compliant vehicles. In fact, due to non-compliancy, the Diesel engine has taken a massive hit with sales dropping to an all-time low.

Also Read: The Future Of The Diesel Engine

Update Automobile manufacturers need to get rid of their BS4 stock before April as the Supreme Court of India has ruled that no BS4 vehicles will be sold after April 2020.

Billions have been invested in technology, research and development of BS6 fuel compatible engines. Also, with the BS6 upgrade, the cost of manufacturing will shoot up with analysts claiming car prices to soar up by 10%-15%. Luxury carmaker; Mercedes Benz recently introduced their BS 6 ready made-in-India S-Class, way ahead of the deadline.

News: BS 6 Cars Might Get Expensive In 2020!

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Can BS4 cars run on BS6 fuel?

Update [April 2019] The Ministry Of Petroleum And Natural Gas has officially announced that it will start rolling BS6 fuel in Delhi NCR (Gurugram, Noida, Ghaziabad, Faridabad) by April 2019.
Update [October 2019] As of 1st October 2019, the supply of BS6 grade petrol and diesel has started reaching all the petrol station in Delhi and the National Capital Region.

Say you have an old car, pre-2020, BS4 compliant vehicle. You might be wondering if this new BS6 fuel will damage your car. First, let’s get this one straight. If you drive a petrol-powered car, you don’t have to worry about compliance. BS4 petrol and BS6 petrol have very little differences in terms of their chemical composition. Petrol car owners can relax.

Now, this is not the same with diesel though. BS4 diesel had a much higher Sulphur traces (50 ppm), whereas BS6 diesel contains only 10 ppm of Sulphur which is much forgiving for the environment. But why is Sulphur so important? A diesel engine relies on its injector to ionise the fuel for it to become combustible. Sulphur in diesel cars acts as a lubricant for diesel injector. Using BS6 diesel in a BS4 car will cause the injector to wear out prematurely due to less lubrication (low sulphur). This can also inadvertently increase emissions, due to disruption in the flow pattern of the fuel.

New Car Launch: 2019 Hyundai Elantra | Now BS6 Compliant

Can BS6 cars run on BS4 fuel?

Update [July 2019] BS6 ready fuel has reached 60% of fuel stations in Delhi NCR. Will increase to 80% by October 2019 as reported by ET Auto.

Let’s flip the case. You have bought a brand new BS6 compliant car (perhaps the new 2019 Maruti Suzuki Ertiga BS6) and you fuel your car at a petrol station that only stocks old BS4 fuel. Now you wonder, will BS4 fuel damage my BS6 car?

Again, let’s put petrol aside as the chemical composition of both BS4 and BS6 is identically the same. For diesel-powered cars, using BS4 fuel in a BS6 vehicle can cause a host of expensive problems. BS6 diesel engines have very sophisticated electronics and a re-developed exhaust system. With the introduction of DPF (Diesel Particulate Filter) and SCR (Selective Catalytic Reduction), using BS4 diesel with high sulphur content will drastically increase the emission (due to increased sulphur ppm) eventually clogging up the diesel particulate filter. This will also affect the fuel economy in diesel cars.

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What is the difference between BS4 diesel and BS6 diesel?

Unlike, BS6 petrol, BS6 diesel is very different when compared to its BS4 predecessor. The major difference being Sulphur content. BS6 diesel contains upto 5 times fewer sulphur content than BS4 diesel. In fact, BS6 diesel is limited to just 10 mg/kg of sulphur, compared to the 50 mg/kg content in BS4 diesel. This is so to cut down on N20 (Nitrous Oxide) emissions by more than 70%. Using BS4 diesel in a BS6 car can cause serious damage to the fuel delivery system. The increased amount of sulphur will choke the fuel and catalytic convertor. And using BS6 diesel in a BS4 car will result in friction issues due to low sulphur content.

What is the difference between BS4 cars and BS6 cars in terms of performance?

Lowering environmental emissions can really take a hit on a car’s performance. A cleaner engine carries a generally slower combustion process. Adding to this, are major exhaust modifications which further bottlenecks the overall performance of the cars. Therefore, BS6 compliant cars will be down on performance.

However, Indigenous car manufacturers like Tata and Mahindra are pumping investment into their engine and powertrain research and developer to offer a balanced performance proposition for their forthcoming BS6 cars.

What is the difference between BS4 cars and BS6 cars in terms of fuel economy?

The recently launched Bharat Stage 6 equipped petrol Maruti Suzuki Dzire returns a mileage of 21.21 km/l (ARAI Certified) whereas, the outgoing BS4 Maruti Suzuki Dzire returns a mileage of 22 km/l which 0.79 more than the newer “cleaner” BS6 Dzire. As of now, BS6 cars are less fuel-efficient than BS4 cars.

What will be the impact of BS6 on CNG cars?

Carmakers will have to make some minor tweaks with their diesel or petrol engines for using CNG with a BS6 vehicle. CNG cars are already fuel-efficient and way cleaner than petrol or diesel. This does not mean that in the future CNG will not see changes. Once the 2020 BS6 norm in finally implemented, it is only a matter of time that the government will push for even more cleaner CNG.

What will be the cost of BS6 fuel in India?

As per September 2019, the cost of BS6 fuel in India is the same as BS4 fuel. However, there are some strong speculations that BS6 fuel in upcoming days will see a massive price hike. Refineries all over India have invested more than ₹30,000 crores to upgrade their facilities to produce BS6 fuel before the updated emission norms in April 2020.

As reported by NDTV Car & Bike, BS6 Fuel Set To Be More Expensive From April 2020

Will BS4 cars be banned?

Yes, after April 2020. The Supreme Court’s verdict on October 2018 said that sale and purchase of all BS4 vehicles will be banned after April of 2020. The court has even given an ultimatum to car manufacturers to clear their old stock of BS4 vehicles before the deadline. The court has also further made it clear that no extension whatsoever will be given to car companies for old BS4 car stock clearance at any cost.

Update [August 2019] As reported by Finance Minister; Smt Nirmala Sitharaman, BS4 cars purchased till March 2020 will remain operational until the entire period of registration.

Should I buy a BS4 vehicle now?

The India automobile sector is going through a major crisis. With new car sales dropping as high as 30%. The global recession, high-interest rates and the growing second-hand market may be behind this. However, the upcoming BS6 rollout in April 2020 is the biggest reason behind this slump.

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Now is the right time to buy and get a sweet deal on outgoing BS4 vehicles.

First, let’s clear the air on BS4 vehicle validity. The Supreme Court Of India ruled that all BS4 vehicles will continue to ply and be legal on the roads even after BS6 rollout. it is only the sale of BS4 vehicles is going to be ceased after April 2020. Finance Minister Smt. Nirmala Sitharaman said “BS-IV vehicles which are purchased up to March 2020 will remain operational for their entire duration of registration

So, why should you buy a BS4 vehicle now? Here’s why!

  • Huge Discounts: Car manufacturers are now left with a huge inventory full of old BS4 vehicle. To clear up this old stash of cars, major manufacturers like Maruti Suzuki, Hyundai, Tata, Mahindra etc are offering huge discounts on their old inventory. To make the deal more lucrative, car dealers are also offering extended warranty on BS4 cars.
  • More Fuel Mileage: Yes, internal studies have proved that BS4 cars give better fuel economy than their BS6 counterparts.
  • Cheaper Diesel Cars: This is your chance to buy a diesel car with the best discount. BS6 diesel cars compared to BS4 cars are expected to get expensive by upto ₹80,000 to a ₹1,00,000. Therefore, carmakers are offering huge discounts on BS4 diesel cars.

Should I buy a new car now or wait for BS6?

With the recent slump in new car sales, the apprehension to buy a new car is comprehensible. Part of the reason is the Bharat Stage 6 emission norm which is deterring potential buyers from buying a car. Most buyers are simply holding on till April 2020 when BS-6 rolls out. Adding to this, the diminishing future of diesel cars in India. Major carmakers like Maruti Suzuki, VW and Tata are phasing out their diesel inventory.

So, should you buy a car now, or wait for the arrival of BS6? If you are planning to buy a petrol car, you can go ahead with the purchase, as the difference between BS4 petrol and BS6 petrol is insignificant.

But, all is not the same with diesel. With the forthcoming BS-6 upgrade, you can expect a price jump of around a ₹1,00,000 more for a BS6 diesel car. For comparison, a BS6 petrol car will only cost you ₹40,000 to ₹50,000 dearer. You can also bid goodbye to compact diesel engines, as the huge price difference will void any saving you are going to make.

Finally, the question remains, should you buy a diesel car now? We say, YES. Consider buying a small capacity diesel though, as it is the best option for frugality and mile-munching. And if you are planning on keeping a diesel car for more than 5 years, the difference is hardly distinguishable.

What is the difference between a BS6 Compliant and a BS6 Ready car?

A BS ready car simply means that the automobile manufacturer is stating that its existing non-BS6 compliant car is technically and mechanically ready and can be upgraded to be BS6 compliant with just minor tweaks and modification without requiring an engine replacement. The term BS6 ready also means that the car can very easily run on new BS6 fuel without any troubles or complications.

Whereas, a BS6 compliant car is already adhering to BS6 norms straight from the factory by the car manufacturer.

Which is the best BS6 compliant car currently sold in India?

Without waiting for the official roll-out of the BS6 norm on April 1st 2020, car manufacturers have already started rolling out BS6 compliant cars in the Indian market. Hatchbacks, Sedans, SUVs, Luxury you name it, and they have it. So, here is a drop-down of the best BS6 compliant cars currently on sale in India.

  1. Maruti Suzuki S-Presso

    Starting with the little one, the S-Presso is a brilliant little city runner brought to you by Maruti Suzuki. Maruti has done a commendable job in terms of styling the S-Presso. The SUV-ish looks with boxy dimensions give it a “Big Car” appeal. No wonder Maruti Suzuki sold 10,000 units of the S-Presso in the first month of its launch.

    The S-Presso is powered by a 1.0-litre petrol engine which makes 67bhp of power and 90nm of peak torque and claims to deliver a fuel mileage of over 21.7 km/l (ARAI Tested). The S-Presso is priced in the range of ₹3.69 lakhs to ₹4.91 lakhs.

  2. Hyundai Grand i10 Nios

    The Grand i10 Nios came into being as a replacement for the humble and trusty i10. The Hyundai Grand i10 Nios is longer and wider than the outgoing i10. It also a notch ahead in terms of features. One of the highlights that the i10 Nios has is an 8inch touch-screen infotainment system enabled with Android Auto and Apple CarPlay.

    The Grand i10 Nios is available in both petrol and diesel options. While the 1.2-litre petrol engine is BS6 compliant, the 1.2-litre diesel unit is BS6 ready. Both the engines with two transmission options; a 5-speed manual or a 5-speed AMT (automated manual transmission). The power figures for the BS6 compliant engine remains the same as the old i10 producing 83bhp of max power and 114Nm of peak torque.

  3. Maruti Suzuki XL6

    The XL6 or as we call it a “suited-booted Ertiga” is a premium MPV made by Maruti Suzuki. The Maruti Suzuki XL6 is available in two variants and four trim levels; Zeta automatic/manual and Alpha automatic/manual. In comparison to the regular Ertiga, the XL6 is 50mm longer than the former. Distinguishing it from the Ertiga, the XL6 also gets quad-LED headlights, a trapezoidal grille with a sculpted bonnet. The XL6 carries the black-out out theme including on the alloy wheels.

    The Maruti Suzuki XL6 is powered by a BS6 compliant K15 petrol engine with Smart Hybrid technology (SHVS) that produces 103.5bhp and 138Nm of torque mated to either a 5-speed manual or a 4-speed automatic.

  4. Kia Seltos

    How can we forget the Kia Seltos in the list? The Seltos is Kia’s debut offering in the Indian market. Upon its launch, the Kia Seltos was a runaway success garnering more than 50,000 bookings before an official launch. The sales were so good that the Seltos secured good 5th positions in the top-selling cars list of September 2019 selling more than 7,000 units.

    The Kia Seltos is offered in one diesel and two petrol options, all of them being BS6 compliant. The 1.4-litre turbo-GDI petrol engine produces 138 bhp and 242 Nm of peak torque and is available with a 6-speed manual and a 7-speed automatic transmission while the 1.5-litre non-turbo petrol motor does a decent 113 bhp and 144 Nm paired to a 6-speed manual and an i-CVT (Intelligent continuously variable transmission). Lastly, the 1.5-litre VGT diesel produces 113 bhp and 250 Nm of torque and is mated to a 6-speed manual and a 6-speed automatic transmission (torque converter).

  5. Jeep Compass Trailhawk

    The meaner and extreme off-roading version of the Jeep Compass; the Trailhawk was very recently added to Jeep’s portfolio. The Jeep Compass Trailhawk is also the first BS6 compliant SUV by the American manufacturer.

    Offered in a BS6 compliant diesel engine only. The 2.0-litre Multijet II diesel engine develops a healthy 168 bhp and 350 Nm of peak torque and is mated to a 9-speed automatic gearbox.

  6. The Mercedes Benz S 350D

    Do you want a luxurious BS6 compliant car? Mercedes Benz has got your back! The grand “S” or the Mercedes Benz S 350D should be your choice. In fact, Mercedes Indian became the first car manufacturer in the country to roll-out a BS6 compliant car way before others followed.

    The Mercedes Benz S 350D is powered by a 2987CC in-line 6 cylinder developing a smooth and linear 282 bhp and 600 Nm of peak torque through a 9-speed automatic transmission.

Upcoming BS6 cars in 2020

  1. 2020 Ford Ecosport BS6
  2. 7th-Gen Honda City
  3. 2020 Toyota Raize SUV
  4. Next-gen Toyota Innova
  5. New Hyundai Verna BS6
  6. 2020 Skoda Octavia
  7. 2020 Mahindra XUV 500

Other BS6 compliant cars available in India

  1. Maruti Suzuki Ertiga Petrol (1.5-litre K15B Smart Hybrid Petrol)
  2. Toyota Glanza
  3. Maruti Suzuki Alto 800
  4. Mahindra Bolero Power Plus (1.5-litre, Three-Cylinder, Turbo-Diesel)
  5. Maruti Suzuki WagonR 1.2
  6. 2019 Mercedes Benz E200e and E200d (2.0-liter Petrol and Diesel)
  7. Mercedes Benz V Class

Must Read: 10 Best BS6 (Bharat Stage 6) Cars To Buy This Diwali

Huge Relief For Automobile Sector | From BS6 to Electric Vehicles: Read it here

Akshat Ajeya
Akshat Ajeya
Lead, Content & Creatives at GoMechanic | Automobile Scale Model Collector | DIY guy | Consumer of many foods | CVT is not that bad


    • NO, not yet. However, a new facelifted Nexon has been spied and is speculated to come equipped with a BS6 compliant engine.

  1. You are saying it’s right time to buy diesel cars due to huge discount but also saying post April 2020 due to bs 6 diesel will affect bs4 diesel car due to low sulfur……confused?

    • The effect of BS6 diesel on BS4 cars is not to that extent that it can totally destroy the engine. With regards to buying a BS4 diesel car, yes it is a good time as manufacturers are clearing out their old BS4 inventory.

  2. In your earlier comment, you said, we can buy BS4 diesel there is not much difference between BS4 and BS6 diesel. Are you not contradicting to the statement “Using BS4 diesel in a BS6 car can cause serious damage to the fuel delivery system. The increased amount of sulphur will choke the fuel and catalytic convertor. And using BS6 diesel in a BS4 car will result in friction issues due to low sulphur content”?

    • Using BS6 diesel in a BS4 diesel car will have some effect on the fuel and ignition system. This is due to the low sulphur content in BS6 diesel fuel.
      BS4 diesel fuel, on the other hand, has a greater sulphur level which can damage vital components if used in a BS6 diesel car.

  3. Hi, very informative though. Can you clarify if BS4 diesel will also be available to feed in BS4 diesel engines, because BS4 diesel cars will definitely be owned after April 2020 deadline.

    • As per recent updates, Indian oil companies have starting phasing towards producing and transporting BS6 fuel at their respective petrol pumps. Using BS6 diesel in a BS4 car will have some effect on the engine due to the low sulphur content.

  4. I am planning to buy Ertiga 2019 1.5 Diesel since the weighting period for petrol is high.. Can I wait or go ahead with diesel ??

    • You can go for the Diesel Ertiga provided you get a good discount from Maruti. Else, we recommend you wait for the Petrol Ertiga.

  5. Very nice to understand. Am working for real estate company in oragadam. Most people don’t no what is BS6. I my self explain to the people.on reading your feedback. Very excellent and Wounderful sir.
    Thank you.

  6. I have booked maruti suzuki new baleno zeta petrol. Dealer saying it is BS 6 car.
    Please suggest if it it BS 6 ready or BS 6 complaint
    Thank you

    • A BS4 engine can be BS6 ready which means that the BS6 fuel can be used. But BS6 compliant means that the engine’s initial designs are already following the BS6 norms. For a BS6 ready engine, there needs to be some tuning and upgrades for the engine to comply with the new norms. It is therefore recommended to buy a BS6 compliant car if you are looking for a new one.

  7. BS6 will reduce the pollution but, Indian govt. also need to think of the vehicles on road which are of BS4 and lower version. Because they will pollute the air at the same rate before implementation of BS6 vehicles.

    • The government is also planning to introduce vehicle scrapping policy for the vehicles which are not environmental friendly. Government is really working towards the better future of mobility and we, as a citizen need to help the government too.

  8. see BS6 fuel dont harm BS4 engines :- After combustion, sulfur from diesel fuel creates sulfuric acid that causes caused corrosive wear on the metal surfaces of an engine. Corrosion of a surface within in a dynamic system such as the cylinder wall/liner can lead to corrosive wear; surface corrosion layers are removed through sliding or abrasion.

    All acids formed within the engine have the potential to cause corrosion, but the risk of corrosion depends on their acidity. The acidity of a fluid is measured according to the mixture’s “pH”. Both the concentration (amount) of acid present, and the strength of the acids in the mixture, will increase the risk of corrosion.

    • Hi Mathew,
      We’d like to mention it is the BS6 diesel we are talking about here that will SURELY harm the diesel engine running on BS4 fuel. Sure, the sulphur from the fuel does from sulphuric acid but is on not until it enters the exhaust. Because of the combustion of sulfur-rich diesel, it forms different oxides of sulphur (mainly SO2 and SO3). This later, in the exhaust system, reacts with the water vapours in the atmosphere and forms sulphuric acid.

      Moreover, the BS6 diesel contains no sulphur, meaning it will not lubricate the internal parts, (like the pump and the injectors and less longevity.

  9. It was necessary for someone to write on this topic and you grabbed the heart of millions by taking the initiative which is enough to bring the evolution. Thanks for bringing it in light.

  10. The title of your write-up is very eye catchy which holds an individual to read till the very end of your blog. Every new paragraph increases the interest of a reader.


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