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Difference between BSIV & BSVI Engine: BS4, BS6 Performance

  • Author :
  • TATA AIG Team
  • Published on :
  • 15/09/2022

Pollution is a serious issue in our country. It degrades the environment and causes different types of respiratory issues in humans. One of the most common causes of increasing pollution and harmful emissions is the use of automobiles. Therefore, regulating the emission in vehicles becomes important. The Central Pollution Control Board(CPCB) introduced the Bharat Stage Emission Standards(BSES) that regulate the pollution emitted in four-wheelers and two-wheelers. Vehicles must comply with these standards, considering the safety of the environment and people.

The Central Government mandated that vehicle manufacturers should sell only BS6(BSVI) vehicles starting from 1st April 2020. Here is a detail about BS6 meaning and how it differs from BS4(BSIV).

What Are BS4 (BSIV) and BS6 (BSVI)?

The BSES was first introduced in 2000. Hence, the first emission norm is referred to as the 'India 2000'. Later, BS2 and BS3 were introduced in the year 2005 and 2010, respectively.

Finally, the BS4 norms were introduced in 2017 and had stricter emission standards. The BS4 full form is Bharat Stage Emission Standards 4. BS6 is the sixth version of the emission standards. It skipped BS5 and has the best and the most stringent emission norms. The BS6 full form is Bharat Stage Emission Standards 6. These emission standards regulate the output of pollutants by determining the permissible level for the vehicles in the country.

Difference Between BS4 and BS6 Emission Norms

The Central Pollution Control Board sets pollution emission standards and regulates the pollutants released from the spark ignition and internal combustion motors in vehicles. BS4 and BS6 are the last two emission norms. The Government has prohibited producing and manufacturing vehicles that meet the emission standards BS4 from 1st April 2020. It has reduced the level of pollution to a great extent. Here is a table describing the extent of the permissible levels of different pollutant gases.

Type of Fuel Pollutants BS4 BS6
Petrol Nitrogen Oxide(NOx),Particulate Matter(PM) 80mg,Nil 60mg,<4.5mg/km
Nitrogen Oxide(NOx) 250mg <80mg
Diesel Particulate Matter(PM),HC + NOx 25mg/km,300mg/km <4.5mg/km,170mg/km

As we can see, the extent of permissible pollutants has been changed to a greater extent in petrol and diesel vehicles in BS6. The BS4 meaning was that it allowed for emitting less than 80mg/km of Nitrogen Oxide(NO). The BS6 reduced it to 60mg/km in petrol vehicles. And, in diesel vehicles, it is reduced from 250mg/km to 80mg/km.

The particulate matter limit is restricted to 4.5mg/km in both petrol and diesel cars. In addition, the HC + NOx limit for diesel vehicles was reduced from 300mg/km to 170mg/km in the BS6 emission norms.

Other notable changes in the BS4 and BS6 are:

  • The regulators introduced the Diesel Particulate Filter (DPF) and the Selective Catalytic Reduction (SCR) to monitor the emission levels in BS6 motor vehicles. However, it was not present in the BS4 norms.
  • The Onboard Diagnostic is a facility in BS6 that was not introduced in BS4.
  • The Real Driving Emission(RDE) is introduced in BS6 motor vehicles to monitor the regulations on a real-time basis that was not present in the BS4 norms.

Difference Between BS4 and BS6 Fuels

One of the main BS4 and BS6 differences is the type of fuel these engines take. The sulphur concentration in BS4 fuel is 50ppm, which is reduced fivefold in BS6 fuel to 10ppm. Therefore, BS6 fuel is comparatively cleaner than BS4. It contains less sulphur and reduces harmful pollutants and emissions. Sulphur is required for the lubrication process. BS4 uses real sulphur, and BS6 utilises compounds that can provide sulphur's lubricating properties.

If a BS6 motor uses the BS4 fuel, the emission norms stand violated. Therefore, a BS6 engine must use the BS6 fuel. When you compare the BS4 vs BS6 engine, the BS6 engine is considered the best as it increases the longevity of the BS6 engine and the car. While the Bharat Stage Emission Standards help regulate emissions, it is equally important that you have a car insurance policy to manage the repair costs in the event of an unexpected accident. Insurance providers offer a range of products you can customise based on your car, geographical location, and affordability.

At Tata AIG, we offer different four-wheeler insurance plans with add-on covers to help maximise the financial benefits. Also, we offer cashless claim and reimbursement benefits in a good number of garages throughout the country. We also provide the option to purchase, modify and renew our car insurance plans online. Therefore, you can view the different products, compare car insurance based on the features and cost and decide on the best car insurance product based on your requirements.


The Central Pollution Control Board (CPCB) introduced the Bharat Stage Emission Standards (BSES) to regulate automobile emissions. The regulatory body states the limits for the different types of pollutants from internal combustion. The limit of harmful pollutants has been decreased to a greater extent in the BS6 compared to the BS4 emission norms. In addition, specialised facilities and diagnostics are introduced in the BS6 to monitor emissions in real-time.

While ensuring such emission standards, it is equally important to have a car insurance policy to help you manage the financial crisis in the event of an accident resulting in extreme damages. Therefore, comply with the rules and regulations, secure your car with the right car insurance plan and live at peace!

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