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BS 6 is the new emission standard that all vehicles in the country will have to adhere to from April 1, 2020. The sale of BS-4 vehicles will also cease from this day. The Supreme Court had ruled on October 24 2019 that no BS-4 vehicle would be sold with effect from April 1, 2020. Bharat Stage Emission Standards are emission regulations implemented by the government to keep a check on emissions from motor vehicles.

Decoding the term ‘BS’:

  • To start with, the ‘BS’ in BS VI stands for ‘Bharat Stage’ which signifies the emission regulation standards set by Indian regulatory bodies.
  • The ‘VI’ is a roman numeric representation for six (6). The higher the number gets, the stricter the Bharat Stage emission norms get which eventually means it becomes trickier (and costlier) for automakers to meet them.
  • These emission standards were set by the central government to keep a check on the pollutant levels emitted by vehicles that use combustion engines. To bring them into force, the Central Pollution Control Board sets timelines and standards which have to be followed by automakers.
  • Also, the BS norms are based on European emission norms which, for example, are referred to in a similar manner like ‘Euro 4’ and ‘Euro 6’. These norms are followed largely by all automakers across the globe and act as a good reference point as to how much does a vehicle pollute.
  • To wrap it up and put it simply, Bharat Stage emission norms are largely similar to the European emission norms followed globally.

Difference between BS-IV and the new BS-VI:

  • The major difference in standards between the existing BS-IV and the new BS-VI auto fuel norms is the presence of sulphur.
  • The newly introduced fuel is estimated to reduce the amount of sulphur released by 80%, from 50 parts per million to 10 ppm
  • As per the analysts, the emission of NOx (nitrogen oxides) from diesel cars is also expected to reduce by nearly 70% and 25% from cars with petrol engines.

 Why is it important to upgrade these norms?

  • Upgrading to stricter fuel standards helps tackle air pollution.
  • Global automakers are betting big on India as vehicle penetration is still low here, when compared to developed countries.
  • At the same time, cities such as Delhi are already being listed among those with the poorest air quality in the world. The national capital’s recent odd-even car experiment and judicial activism against the registration of big diesel cars shows that governments can no longer afford to relax on this front.
  • With other developing countries such as China having already upgraded to the equivalent of Euro V emission norms a while ago, India has been lagging behind. The experience of countries such as China and Malaysia shows that poor air quality can be bad for business. Therefore, these reforms can put India ahead in the race for investments too.

BS IV engine change to BS VI engine: Following changes needs to be done:

  • Although the BS-4 car can run on BS-6 Fuel, but what will happen if we defer our purchase
  • Emission: Cleaner fuel as the sulphur levels will be lower and lower PF (Particulate Filter). Thus, the emissions will be relatively much lower than what emit by cars.
  • Also, our BS-6 Car will get latest Technology and updates including changes in Catalytic, Diesel Particulate Filter, Fuel Injection for better compliance to Emission. Care for Environment – you should defer your purchase call
  • Engine Performance: The Sulphur levels will be lower, thus acids as formed will be lower and also the engine oil live will improve.
  • Even the fuel would be much cleaner and thus care for better efficiency from our car in terms of improved Engine Oil Life, Engine Performance, Engine NVH Levels you will get all these benefits with BS-6 Fuel
  • Fuel Efficiency: Been the fuel in BS-6 regime would be much cleaner – the overall fuel efficiency can also jump in when used a BS-6 compliant car using BS-6 Fuel grade.
  • Safety Features: ABS, Airbags would be standard all across model Variants as sold from 2020. Even crash test regulations would be improved.
  • It involves Selective Catalytic Reduction (SCR), which is an advanced active emissions control technology.
  • SCR converts nitrogen oxides to nitrogen, water, tiny amounts of CO2 by pumping in automotive grade liquid urea, which is known as Diesel Exhaust Fluid (DEF).
  • It achieves NOx reductions up to 90%. Tailpipe Particulate Matter filter is used.
  • This reduces the Particulate Matter coming out of the vehicle to the required level.

Will the vehicles with BS-VI tech become expensive?

  • The everyday customer who is yet to buy themselves a vehicle or is planning to get one could soon have to shell out more for their purchase.
  • On top of that, the fuel costs also need to be taken into account. But above all of this, there is a bigger target to be achieved. India has some of the most polluted cities in the world and automobiles are often considered as one of the biggest factors responsible for it.
  • The need of the hour is to control the pollution levels by all means possible and since globally, countries are implying Euro 6 levels of emission regulations, India needs to step up its game and hence the BS IV to BS VI emission norm implication.


  • This outcome should be welcomed for the positive impact it will have on air quality and public health.
  • At every stage, the technology is increasingly more complex. To attain the specified super low emissions, all reactions have to be precise, and controlled by microprocessors.
  • So, for carmakers, skipping the diesel value chain at this point makes more sense.
  • Alongside the constraints faced by carmakers, there are also question marks regarding the ability of the oil companies to manage the transition, given that the full transition to BS-IV took from 2010 to April 2017 because refiners were unable to produce the superior fuel in required quantities.
  • Improving air quality in the cities requires a transformative planning approach guided by the singular objective of reducing the use of polluting vehicles.