Bharat Stage 4 and 6 Emission Standards: Vehicle Engine Regulations

Bharat Stage 4 (BS4) and Bharat Stage 6 (BS6) emission standards are key regulations in India designed to control vehicle emissions and improve air quality. BS4, implemented from April 1, 2017, required vehicles to meet stricter limits on pollutants like carbon monoxide, hydrocarbons, nitrogen oxides, and particulate matter compared to its predecessor, BS3. It also mandated the use of improved catalytic converters and better engine management systems. BS6, which took effect nationwide from April 1, 2020, represents a significant advancement over BS4. It introduces much stricter emission limits, particularly for nitrogen oxides and particulate matter, and requires the use of advanced technologies such as selective catalytic reduction (SCR) for diesel engines and improved catalytic converters for petrol engines. BS6 fuels have a substantially lower sulfur content, which is critical for these advanced technologies to work effectively. This transition from BS4 to BS6 marks a substantial step forward in reducing vehicle emissions and combating air pollution in India.

What are BS4 and BS6 standards?

The BS4 standards started in 2017 with stricter pollution rules. BS4 stands for Bharat Stage Emission Standards 4. BS6 is the latest, skipping BS5. It has the toughest rules to cut pollution. BS6 stands for Bharat Stage Emission Standards 6. These rules control how much pollution vehicles can emit in India.

To control car and bike pollution, India's government made Bharat Stage Emission Standards (BSES) rules.

The government says all vehicle makers must only make, sell, and register BS6 (BSVI) vehicles from April 1, 2020

What is BS4 ?

The organization responsible for regulating vehicle emissions, known as BSES, initiated the first set of emission standards called 'India 2000' in the year 2000. Subsequently, BS2 and BS3 standards were introduced in 2005 and 2010, respectively. The implementation of BS4 norms began in 2017, characterized by more stringent emission requirements compared to previous standards.

The governing body made various changes to emissions rules, like tailpipe emissions and electronic controls. One big change was AHO (Automatic Headlamp On) for safety, a rule under BS4 standards. this is one of the norms under the BS4 which catered to the safety aspect of the new emission standards.

What is BS6 ?

The BS6 emission standard is the latest version, and it's a big step forward in reducing pollution compared to BS4. They skipped BS5 to go straight to BS6 for even cleaner air.

BS VI fuel has lower levels of sulphur, the main polluting agent in fuels. Removal of sulphur from fuel is a complex process and it costs as much, making fuel costlier to buy.

Difference between BS4 and BS6 standards :

The main differences between BS4 and BS6 pollution rules are:

1. BS6 limits Nitrogen Oxides (NOx) emissions to 60mg/km for petrol vehicle, compared to 80mg/km in BS4.

2. For petrol vehicle, BS6 limits Particulate Matter (PM) to less than 4.5 mg/km.

3. Diesel vehicle under BS6 have NOx emissions capped at 80 mg/km, down from 250 mg/km in BS4.

4. Hydrocarbon+NOx emissions in diesel vehicle under BS6 are capped at 170 mg/km, lowered from 300 mg/km in BS4.

5. Both diesel and petrol vehicle under BS6 have PM limits of 4.5 mg/km, whereas diesel vehicle under BS4 had a limit of 25 mg/km.

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What are the Bharat Stage Emission Standards (BSES) BS4 and BS6?

The Central Pollution Control Board, under the Ministry of Environment, Forest, and Climate Change, establishes emission standards and timelines for controlling air pollution from internal combustion and spark-ignition engines used in motor vehicles.

Before delving into engine types and pollution emissions of BS4 and BS6, let's understand how it all began. Emissions regulations started with 'India 2000' in 2000, followed by BS2 and BS3 in 2005 and 2010, respectively. In 2017, BS4 norms were introduced. Every vehicle manufactured after these norms must comply. In 2016, the Indian government decided to skip BS5 and transition directly to BS6 by 2020. The sale and registration of vehicles not meeting BS6 standards were banned from April 1, 2020, per a Supreme Court ruling. This move aimed to address worsening pollution issues, particularly noticeable around 2019. The adoption of BS6 aims to reduce pollution levels.

Can I drive BS4 vehicle on BS6 fuel?

If you have a petrol car, you can use BS6 fuel in a BS4 vehicle without much impact on the engine. BS6 fuel has less sulfur, so emissions are reduced, but it might slightly affect power and fuel efficiency. However, it's trickier for diesel cars. BS6 diesel fuel has less lubrication, which can affect fuel injectors and engine performance. Using fuel additives can help improve lubrication and prevent damage to BS4 diesel engines.

The main differences between BS4 and BS6 pollution rules are:

1. BS6 limits Nitrogen Oxides (NOx) emissions to 60mg/km for petrol vehicle, compared to 80mg/km in BS4.

2. For petrol vehicle, BS6 limits Particulate Matter (PM) to less than 4.5 mg/km.

3. Diesel vehicle under BS6 have NOx emissions capped at 80 mg/km, down from 250 mg/km in BS4.

4. Hydrocarbon+NOx emissions in diesel vehicle under BS6 are capped at 170 mg/km, lowered from 300 mg/km in BS4.

5. Both diesel and petrol vehicle under BS6 have PM limits of 4.5 mg/km, whereas diesel vehicle under BS4 had a limit of 25 mg/km.

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What are the benefits of BS6 standards?

• Eco-conscious Driver:
With BS6 compliant cars, you can drive vehicles prioritizing emission reduction for cleaner air, making you an environment warrior.

• Reduced NOx Emissions:
Opting for a BS6 petrol model cuts combustion-based emissions by 25%.

• Environmental Responsibility:
Choosing BS6 vehicles aligns with global norms, fostering environmental conservation.

•Advanced Technology:
BS6 offers fuel-efficient engines with real-time emission monitoring systems.

• Cleaner Combustion:
Advanced engines minimize pollutants like PM and NOx, ensuring a greener driving experience.

• Technological Advancements:
The lineup includes eight BS6 compliant models, showcasing cutting-edge technology.

•Fuel Compatibility:
BS6 petrol vehicles are compatible with BS4 fuel, offering flexibility in fuel usage.

• Climate Contribution:
Embracing BS6 technology supports India's commitment to reducing carbon emissions per the Paris Climate Agreement.

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