Bharat Stage (BS) Emission Norms are standards instituted by the government of India to regulate the output of air pollutants from internal combustion engine equipment, including motor vehicles. BS standards and the timeline for implementation are set by the Central Pollution Control Board under the Ministry of Environment, Forest and Climate Change. It was first introduced in the year 2000.
The norms are based on European regulations (Euro norms), and each stage specifies a certain limit on the pollutants released, which is controlled by the type of fuel made by oil companies and the upgrades and modifications made by auto companies in the engines and exhaust systems.
The stages are typically written as ‘Bharat Stage’ followed by the corresponding Roman numeral. For example, Bharat Stage VI (BS-VI) is the sixth stage of the Bharat Stage Emission Norms, which came into effect on April 1, 2020, throughout India.
The Bharat Stage emission standards regulate tailpipe emissions of air pollutants including particulate matter, SOx and NOx as well as carbon monoxide, hydrocarbons and methane.
Bharat Stage emission
| Standard | Reference | Year | Region |
|---|---|---|---|
| India 2000 / Bharat Stage I | Euro 1 | 2000 | Nationwide |
| Bharat Stage II | Euro 2 | 2001 | NCR, Mumbai, Kolkata, Chennai |
| 2003 | NCR, 14 Cities† | ||
| 2005 | Nationwide | ||
| Bharat Stage III | Euro 3 | 2005-04 | NCR, 14 Cities† |
| 2010 | Nationwide | ||
| Bharat Stage IV | Euro 4 | 2010 | NCR*, 14 Cities† |
| 2017 | Nationwide | ||
| Bharat Stage V | Euro 5 | (Skipped) | |
| Bharat Stage VI | Euro 6 | 2018 | Delhi |
| 2019 | NCR* | ||
| 2020 | Nationwide | ||
| Bharat Stage VI Phase 2 | 2023 | Nationwide |
BS-I
Implementation: BS-I was first introduced in 2000 for four-wheeled vehicles in Delhi, and it was extended to other metros in 2001.
This stage introduced the mandatory fitment of catalytic converters in petrol vehicles. The converters helped reduce the emission of carbon monoxide (CO), hydrocarbons (HC), and nitrogen oxides (NOx).
light-duty vehicles (Petrol) | Two-wheelers | light-duty vehicles (Diesel) | |
|---|---|---|---|
| Carbon Monoxide (g/km) | 2.72-6.90 | 2 | 2.72–6.90 |
| HC (g/km) | – | – | – |
| NOx (g/km) | – | – | – |
| PM | – | – | 0.14-0.25 |
| HC+NOx (g/km) | 0.97-1.70 | 2 | 0.97-1.70 |
BS-II
BS-II was implemented in 2001 for four-wheeled vehicles in Delhi, and it was extended to other metros in 2003.
The major change in this stage was the introduction of more advanced technology and stricter emission limits for pollutants like CO, HC, and NOx.
The stricter norms led to the improvement in emission control systems in vehicles, resulting in reduced pollution levels.
light-duty vehicles (Petrol) | Two-wheelers | light-duty vehicles (Diesel) | |
|---|---|---|---|
| Carbon Monoxide (g/km) | 2.2-5.0 | 1.5 | 1.0–1.5 |
| HC (g/km) | – | – | – |
| NOx (g/km) | – | – | – |
| PM | – | – | 0.08-0.17 |
| HC+NOx (g/km) | 0.5-0.7 | 1.5 | 0.7–1.2 |
BS-III
BS-III was implemented in 2005 for four-wheeled vehicles in the entire country.
This stage introduced the use of electronic control units (ECUs) in vehicles to better monitor and control emissions. It also set more stringent limits for pollutants like CO, HC, and NOx.
The implementation of BS-III norms led to the development of more advanced engine technologies, improved fuel quality, and enhanced emission control systems.
light-duty vehicles (Petrol) | Two-wheelers | light-duty vehicles (Diesel) | |
|---|---|---|---|
| Carbon Monoxide (g/km) | 2.3 | 1 | 0.64 |
| HC (g/km) | 0.2 | – | – |
| NOx (g/km) | 0.15 | – | 0.5 |
| PM | 0.05 | – | 0.05 |
| HC+NOx (g/km) | 0.35 | 1 | 0.56 |
BS-IV
BS-IV was implemented in 2010 for NCR* and 14 Cities and in 2017 for the rest of the cities in the country for four-wheeled vehicles.
This stage required the use of advanced emission control technologies such as advanced exhaust gas recirculation (EGR) systems and selective catalytic reduction (SCR) systems to further reduce pollutants like particulate matter (PM) and NOx.
The introduction of BS-IV norms resulted in a significant reduction in vehicular pollution, especially in urban areas.
light-duty vehicles (Petrol) | Two-wheelers | light-duty vehicles (Diesel) | |
|---|---|---|---|
| Carbon Monoxide (g/km) | 1 | 1.97 | 0.5 |
| HC (g/km) | 0.1 | – | – |
| NOx (g/km) | 0.08 | 0.39 | 0.25 |
| PM | – | – | – |
| HC+NOx (g/km) | – | 0.20 – 0.79 | 0.025 |
BS-V
The Indian government decided to skip this stage and move directly to Bharat Stage VI to meet international standards.
BS-VI
BS-VI was implemented nationwide in 2020 for four-wheeled vehicles.
The implementation of BS-VI norms also means that car manufacturers have to equip their vehicles with advanced emission control devices. For petrol vehicles, manufacturers have to install a three-way catalytic converter; diesel vehicles have to install a Diesel Particulate Filter (DPF).
The transition to BS-VI norms is a significant step towards reducing vehicular pollution in India. However, it also means that the cost of vehicles has increased due to the advanced technology and devices required to meet these norms. The cost of fuel has also increased due to the lower Sulphur content and the higher refining costs associated with it.
light-duty vehicles (Petrol) | Two-wheelers | light-duty vehicles (Diesel) | |
|---|---|---|---|
| Carbon Monoxide (g/km) | 1 | 1 | 0.5 |
| HC (g/km) | 0.1 | 0.1 | – |
| NOx (g/km) | 0.06 | 0.06 | 0.08 |
| PM | 0.0045 | 0.0045 | 0.0045 |
| HC+NOx (g/km) | 0.16 | 0.068 | 0.17 |
BS-VI Phase 2
BS VI Phase 2 was introduced in April of 2023. The BS6 Phase 2 emission norms reduce the emission limits for NOx, PM, and CO even further than the BS6 norms.
The main difference between the BS6 phase 1 and the BS6 phase 2 norms is that the BS6 phase 2 compliant models must comply with the emission standards in real-world conditions, apart from the laboratory testing, whereas the vehicles required for the first stage are tested only in laboratories. So, RDE (Real Driving Emission) have been implemented to check the emission while the engine is running. It focuses on real driving emissions and all the vehicles will now come with an OBD 2 (On Board Diagnostic) system to monitor real-time emission levels.
Impact of Bharat Stage Emission Norms
The Bharat Stage (BS) emission standards have had a significant impact on the automotive industry in India. Manufacturers have had to invest heavily in upgrading their technologies to meet the increasingly stringent norms. This has led to an increase in the cost of vehicles, but it has also spurred innovation and the development of cleaner, more efficient engines. Also, you would no longer see small cars with diesel engines.
The norms have also had a significant impact on air quality and climate change. By reducing the permissible levels of pollutants that vehicles can emit, they have helped to reduce the levels of harmful air pollutants in India’s cities. This has benefits for public health, as well as for the climate, as many of these pollutants contribute to global warming.
However, the effectiveness of the norms in combating pollution and climate change is dependent on their enforcement. There have been concerns about the lack of adequate testing and enforcement infrastructure in India, which could undermine the effectiveness of the norms.
Overall the impact is positive for us and our environment. Diesel cars are getting more expensive, which is a good sign as they emit more than petrol cars. That doesn’t mean petrol cars emit less, but with stringent norms, auto manufacturers are forced to make more efficient hybrid and electric cars, which are far better when compared to diesel and petrol cars. At last, I would like to say we as a consumer and the government have a good chance to make our public transport stronger so that we can reduce cars on the road.
