Bharat Stage-6 | Bharat stage 6 Norms | BS 6 in 2020

Bharat stage 6:-
Nowadays the introduction of Bharat Stage-6 / BS VI / BS 6 technology in Indian Automotives is one of the hottest news. It is the big leap for Indian Automotive Sector as with the introduction of Bharat Stage 6 technology, Indian Automotive sector will be able to cope up with European and American Vehicle Industries in terms of Emission Norms.
What is Bharat stage 6?
Bharat stage 6 is the Emissions Norms that will strickly follow in India from 2020. With the introduction of Bharat Stage 6 technology, Indian Automotive sector will be able to cope up with European and American Vehicle Industries in terms of Emission Norms.
What is Emission?
Emissions are the byproducts of any reaction. In case of Automobiles which employ Internal Combustion Engine as a powerhouse, fuel is ignited inside the engine. So due to the burning of fuel produces exhaust gases as byproducts which in technical terms is termed as ‘Tailpipe Emissions’.
What are Emission Norms?
Emission Norms are a set of standards which define the quantity of each pollutant from vehicle per distance of the run. Central pollution control Board implemented the emissions Norms in India under the Ministry of Environment, Forest and Climate Change.
How Emissions Norms controlled?
When we are talking about Automotive Engine there is a number of factors that need to be controlled. Like Engine needs Fuel and Air for operation. Now the twist is Engine will respond differently to different temperatures, pressures, volumes, etc of Intake Air. (To know more about Automotive Engine or Internal Combustion check out our article on IC Engine Working and Operation). The sensors are used to measure and sense various parameters like Intake air pressure, intake temperature and many more.
Bharat stage:-
If we talk about Bharat Stage 4 Norms which imposed in India in 2010 but strictly imposed in 2017, companies offered a huge discount on vehicles on March 31st, 2017 as from April 1st, 2017 Bharat Stage 3 vehicles were to be banned. But this scenario does not seem to happen in 2020 April, as companies are planning their strategies for 2020 well before. Some of the vehicles are even coming into market Bharat stage 6 ready like Royal Enfield 650 Twins. It is appreciable step by Govt of India to skip BS V Emission Norms.
Now for most of the people who are not technical in the Automotive sector, these terms are not familiar. They only know that Bharat Stage or BS term refers to emissions norms, but how emissions are reduced, they are not familiar with it. So, Revjust is bringing the series of articles where you can go in technical detail into these technologies.

Emissions:-
Emissions are the byproducts of any reaction. In case of Automobiles which employ Internal Combustion Engine as a powerhouse, fuel is ignited inside the engine. So due to the burning of fuel produces exhaust gases as byproducts which in technical terms is termed as ‘Tailpipe Emissions’. But tailpipe emissions are not only the concern here. There is another term often known as ‘Non-Tailpipe Emissions’. Non-Tailpipe Emissions are emissions which occur due to evaporation of fuel or oil into the air. These are termed as ‘Non-Tailpipe Emissions’ because these emissions do not come into the environment directly from the tailpipe.
Before going into technical details of BS-VI / BS-6/Bharat stage 6 let us have an outlook on what are emissions from vehicles that need to be controlled. As the majority of Automobiles, today employ Internal Combustion Engines as a powerhouse, so it is quite obvious that there will be some emissions due to the burning of fuel inside the engine. These emissions also known as exhaust gases. These emissions consist of various gases and toxic elements depending on fuel type, fuel purity, engine health, operation, and many others.
Bharat stage 6 Emission Norms.
What are Emission Norms?
Emission Norms are a set of standards which define the quantity of each pollutant from vehicle per distance of the run. Central pollution control Board implemented the emissions Norms in India under the Ministry of Environment, Forest and Climate Change.
Now as I stated earlier there are many gases which are part of tailpipe emissions. Each constituent of emission is the result of different factors, like some pollutants are only noticed when the engine temperature is excessively high, some are due to Air-Fuel mixture ratios disturbance and many other factors. The major pollutants that are noticed in Diesel Engine are:
- Hydro Carbons (HC)
- Nitrox (NOX)
- Hydro Carbons (HC) and Nitrox (NOX)
- Carbon Monoxide (CO)
- Particulate Matter (PM)
For petrol vehicles the major pollutants are:
- Hydro Carbons (HC)
- Nitrox (NOX)
- Hydro Carbons (HC) and Nitrox (NOX)
- Carbon Monoxide (CO)
How Emissions Norms controlled?
When we are talking about Automotive Engine there is a number of factors that need to be controlled. Like Engine needs Fuel and Air for operation. Now the twist is Engine will respond differently to different temperatures, pressures, volumes, etc of Intake Air. (To know more about Automotive Engine or Internal Combustion check out our article on IC Engine Working and Operation). The sensors are used to measure and sense various parameters like Intake air pressure, intake temperature and many more.
Actuators are used to control the parameters. Basically, actuators are devices that are used to convert one form of energy to another like an electrical signal to mechanical output. These actuators are controlled by a central control unit known as the Electronic Control Unit (ECU) or Electronic Control Module (ECM). The ECU gets its input from various sensors measuring various parameters. All the game is how these parameters is controlled using sensors.
Till April 2020 India will be running on BS-IV/ BS-6 norms. From April 2020 BS-VI norms will be made mandatory in India. BS V norms skipped India to cope up with American and European Automobile Technology.
Now let us start with basic knowledge of Pollutants that need to be controlled.
Unburned Hydrocarbons:-
- Fuels are basically Hydro Carbons. When these HCs not burned completely due to inappropriate conditions, like less air quantity or poor fuel quality. It results in Unburned HCs particles. These HCs are highly toxic. It consists of Benzene, Particulates and many others. Unburned HC cause smog. Unburned HCs combine with Nitrogen Monoxide (NO) and form Ozone (O3), which is highly poisonous for living beings.
Nitrogen Dioxides:-
- Nitrox generally forms at high temperatures. High Temperature inside the engine creates favorable conditions for the formation of NOX. Basically most commonly found in Nitrox is Nitrogen Monoxide (NO), with small amount of Nitric Dioxide (NO2) and Nitrous Oxide (N2O). As I stated earlier NO is partially responsible for smog formation. It is NO that makes the smog visible by its brownish color. It combines with atmospheric water to form Nitric Acid (HNO3), thus creating Acid Rain.
Carbon monoxide:-
- It is also a result of incomplete combustion of HCs. It is highly toxic to humans. If it reaches human blood cells, it replaces hemoglobin in place of oxygen, thus decreasing the quantity of oxygen reaching the organs. CO binds more strongly to hemoglobin than oxygen.
Particulate Matter:-
- These are more concerned when talking about Diesel Engine Emissions. These are of size less than one-tenth of size human hair. Their small size makes them highly dangerous for human beings, as they can easily penetrate into human language.
Sulfur Dioxide:-
- The major source of SO2 is sulfur in fuel. Sulfur particles combine with particles and form toxic elements. It can cause asthma and other respiratory problems in human beings.
Beside these all, there are many other pollutants but when concerned with automobile exhaust these are the major pollutants.
Bharat Stage 6 Norms | BS-VI Norms | BS-VI Emission Standards |
As stated in the previous article, Bharat Stage refers to emission norms of automobiles in India. Now let us have the look at what these norms are and how these are different from Bharat Stage 4 Norms.

Bharat stage 6 Emission Norms for Diesel vehicles.
The BS-VI Norms for Diesel vehicles are for majorly Particulate Matter and Nitrogen Oxides / Nitrox (NOX). The emission limits are defined as the amount of pollutant to be emitted per distance of run (gram per kilometer /g/km) or amount of pollutant emitted per unit of specific fuel consumption (g/kWh).
Serial Number | Pollutant | Bharat Stage 4 Norms | Bharat Stage 6 Norms |
Particulate Matter (PM) | ~0.025 g/km | ~0.004 g/km (-82%) | |
Nitrox (NOX) | ~0.25 g/km | ~0.07-0.08 g/km (-68%) |
Table 1.1 Emission Norms comparison between BS-IV and BS-VI Norms for Diesel M1, M2, N1 Class I Vehicles (G Weight < 3500 kg).
Serial Number | Pollutant | BS-IV Norms | BS-VI Norms |
Particulate Matter (PM) | ~0.039 g/km | ~0.004 g/km (-89%) | |
Nitrox (NOX) | ~0.33-0.034 g/km | ~0.1 g/km (-68%) |
Table 1.2 Emission Norms comparison between BS-IV and BS-VI Norms for Diesel N1 Class II Vehicles (G Weight < 3500 kg).
Serial Number | Pollutant | BS-IV Norms | BS-VI Norms |
Particulate Matter (PM) | ~0.059-0.06 g/km | ~0.004 g/km (-93%) | |
Nitrox (NOX) | ~0.37-0.038 g/km | ~0.1-0.13 g/km (-68%) |
Table 1.3 Emission Norms comparison between BS-IV and BS-VI Norms for Diesel N1 Class III, N2 Vehicles (G Weight < 3500 kg).
Serial Number | Pollutant | BS-IV Norms | BS-VI Norms |
Particulate Matter (PM) | ~0.041-0.042 g/km | ~0.004 g/km (-89%) | |
Nitrox (NOX) | ~0.36-0.038 g/km | ~0.07-0.08 g/km (-76%) |
Bharat stage 6 Norms for Diesel Two Wheeler Vehicles
Table 1.4 Emission Norms comparison between BS-IV and BS-VI Norms for Diesel Two Wheeler Vehicles (G Weight < 3500 kg).
Serial Number | Pollutant | BS-IV Norms | BS-VI Norms |
Particulate Matter (PM) | ~0.041-0.042 g/km | ~0.025 g/km (-41%) | |
Nitrox (NOX) | ~0.36-0.038 g/km | ~0.1 (-72%) |
Table 1.5 Emission Norms comparison between BS-IV and BS-VI Norms for Diesel Three-Wheeler Vehicles (G Weight < 3500 kg).
Serial Number | Pollutant | BS-IV Norms | BS-VI Norms |
Particulate Matter (PM) | ~0.029-0.03 g/kWh | ~0.010 g/kWh (-67%) | |
Nitrox (NOX) | ~3.4-3.5 g/kWh | ~0.3-0.4 g/kWh (-87%) |
Table 1.6 Emission Norms comparison between BS-IV and BS-VI Norms for Diesel M, N Transient cycle Vehicles (G Weight > 3500 kg).
Serial Number | Pollutant | BS-IV Norms | BS-VI Norms |
Particulate Matter (PM) | ~0.019-0.020 g/kWh | ~0.010 g/kWh (-50%) | |
Nitrox (NOX) | ~3.4-3.5 g/kWh | ~0.3 g/kWh (-89%) |
Table 1.7 Emission Norms comparison between BS-IV and BS-VI Norms for Diesel M, N Steady cycle Vehicles (G Weight > 3500 kg).
Vehicle categories can be explained as:
M1: 4 wheeler Vehicle for passengers, with a maximum of 8 seats in addition to the driver seat.
M2:4 wheeler Vehicle for passengers, with more than 8 seats in addition to the driver seat.
M3: 4 wheeler Vehicle for passengers, with more than 8 seats in addition to the driver seat and mass exceeding 5 tonnes.
N1: 4 wheeler Vehicle for goods carriage with mass not exceeding 3.5 tonnes.
N2: 4 wheeler Vehicle for goods carriage with mass not less than 3.5 tonnes but not exceeding 12 tonnes.
N3: 4 wheeler Vehicle for goods carriage with a mass exceeding 12 tonnes.
In Bharat Stage 6 / BS-VI Norms the independent limit of Nitrox (NOX) is not defined for three-wheelers. So the limit shown here is Hydrocarbon and Nitrox (HC + NOX).
Emission Norms for Petrol engines.
Now, Bharat Stage 6 / BS-VI Norms for petrol engines majorly focus on pollutants like Hydro Carbons, Carbon Monoxide, Nitrox, Nitrox, and Hydro Carbons Combined.
Serial Number | Pollutant | BS-IV Norms | BS-VI Norms |
Hydro Carbons (HC) | ~0.10 g/km | ~0.10 g/km (0%) | |
Nitrox (NOX) | ~0.08 g/km | ~0.05-0.06 g/km (-25%) | |
NOX + HC0 | ~0 g/km | ~0 g/km (0%) | |
Carbon Monoxide (CO) | ~1 g/km | ~1g/km (0%) |
Table 1.8 Emission Norms comparison between BS-IV and BS-VI Norms for Petrol M1, M2, N1 Class I Vehicles (Light-Duty).
Serial Number | Pollutant | BS-IV Norms | BS-VI Norms |
Hydro Carbons (HC) | ~0.13 g/km | ~0.13 g/km (0%) | |
Nitrox (NOX) | ~0.09 g/km | ~0.07-0.08 g/km (-25%) | |
NOX + HC0 | ~0 g/km | ~0 g/km (0%) | |
Carbon Monoxide (CO) | ~1.8 g/km | ~1.8 g/km (0%) |
Table 1.9 Emission Norms comparison between BS-IV and BS-VI Norms for Petrol N1 Class II Vehicles (Light-Duty).
Serial Number | Pollutant | BS-IV Norms | BS-VI Norms |
Hydro Carbons (HC) | ~0.16 g/km | ~0.16 g/km (0%) | |
Nitrox (NOX) | ~0.1 g/km | ~0.075 g/km (-25%) | |
NOX + HC0 | ~0 g/km | ~0 g/km (0%) | |
Carbon Monoxide (CO) | ~2.25 g/km | ~2.25 g/km (0%) |
Table 1.10 Emission Norms comparison between BS-IV and BS-VI Norms for Petrol N1 Class III Vehicles (Light-Duty).
Serial Number | Pollutant | BS-IV Norms | BS-VI Norms |
Hydro Carbons (HC) | ~0.1 g/km | ~0.1 g/km (0%) | |
Nitrox (NOX) | ~0.38-0.39 g/km | ~0.05-0.06 g/km (-85%) | |
NOX + HC0 | ~0.69 g/km | ~0 g/km (-100%) | |
Carbon Monoxide (CO) | ~1.4 g/km | ~0.9 g/km (-29%) |
Bharat stage 6 Norms for Petrol Two Wheeler Vehicles
Table 1.11 Emission Norms comparison between BS-IV and BS-VI Norms for Petrol Two Wheeler Vehicles, Class 1, 2-1 Vehicles.
Serial Number | Pollutant | BS-IV Norms | BS-VI Norms |
Hydro Carbons (HC) | ~0.1 g/km | ~0.1 g/km (0%) | |
Nitrox (NOX) | ~0.33-0.34 g/km | ~0.05-0.06 g/km (-82%) | |
NOX + HC0 | ~0.62 g/km | ~0 g/km (-100%) | |
Carbon Monoxide (CO) | ~1.9-2.0 g/km | ~1 g/km (-49%) |
Table 1.12 Emission Norms comparison between BS-IV and BS-VI Norms for Petrol Two Wheeler Vehicles, Class 2-2 Vehicles.
Serial Number | Pollutant | BS-IV Norms | BS-VI Norms |
Hydro Carbons (HC) | ~0.1 g/km | ~0.1 g/km (0%) | |
Nitrox (NOX) | ~0.19-0.2 g/km | ~0.05-0.06 g/km (-70%) | |
NOX + HC0 | ~0.39 g/km | ~0 g/km (-100%) | |
Carbon Monoxide (CO) | ~1.9-2.0 g/km | ~1 g/km (-49%) |
Table 1.13 Emission Norms comparison between BS-IV and BS-VI Norms for Petrol Two Wheeler Vehicles, Class 3-1, 3-2 Vehicles.
Serial Number | Pollutant | BS-IV Norms | BS-VI Norms |
Hydro Carbons (HC) | ~0.35 g/km | ~0.35 g/km (0%) | |
Nitrox (NOX) | ~0.15 g/km | ~0.15 g/km (0%) | |
NOX + HC0 | ~0.67-0.68 g/km | ~0 g/km (-100%) | |
Carbon Monoxide (CO) | ~0.75 g/km | ~0.5g/km (-33%) |
Table 1.14 Emission Norms comparison between BS-IV and BS-VI Norms for Petrol Two Wheeler Vehicles, cc<=50, Max Speed 50kmph.
Serial Number | Pollutant | BS-IV Norms | BS-VI Norms |
Hydro Carbons (HC) | ~0.35 g/km | ~0.35 g/km (0%) | |
Nitrox (NOX) | ~0.08-0.09 g/km | ~0.08-0.09 g/km (0%) | |
NOX + HC0 | ~0.9-0.92 g/km | ~0 g/km (-100%) | |
Carbon Monoxide (CO) | ~0.9 g/km | ~0.4 g/km (-53%) |
Table 1.15 Emission Norms comparison between BS-IV and BS-VI Norms for Petrol Three-Wheeler Vehicles.
So, these are basic Bharat Stage 6 / BS-VI Emission Norms for different vehicles. The next article will be on techniques that Automobile Industry uses to satisfy these norms.