What Are Bharat Stage Emission Norms

What are Bharat Stage Emission Norms (BS3, BS4, BS6)?

Many of you must have heard about BS compliance, like BS3, BS4, and now the latest BS6 compliance in the automotive sector. Have you ever wondered what the big deal is about these BS compliances? Well, if you haven’t figured it out yet and are looking for an answer, then we have you covered. 

Bharat Stage Emission Norms, often called BS norms, are a set of regulations and standards established by the Indian government to regulate emissions from internal combustion engine vehicles. These norms play a crucial role in reducing the environmental impact of vehicles by controlling the levels of harmful pollutants they emit into the atmosphere.

The current and latest emission norm is BS-VI which came into effect on April 1, 2020, and is based on the Euro 6 vehicle emission standards. This standard basically dictates the amount of gases a vehicle is allowed to emit. To be more specific, gases like carbon dioxide (CO2), carbon monoxide (CO), hydrocarbons, and oxides of nitrogen are the by-products of an internal combustion engine (IC) engine running.

 In this article, we will explore the evolution of BS norms and delve into the differences between various BS stages.

Understanding the Evolution of BS Emission Norms

BS-I (Bharat Stage I):

Introduced in the year 2000, BS-I marked the beginning of emission norms in India. It was based on the Euro 1 emission standards, and the automakers were to comply with the emission norms starting April 1, 2000. 

It set limits for carbon monoxide (CO), hydrocarbons (HC), and nitrogen oxide (NOx) emissions from petrol and diesel vehicles and adopted catalytic converters to convert the toxic gases into less harmful emissions; for example, CO would be converted to CO2. BS-I was relatively lenient compared to later stages, allowing for higher levels of pollutants.

BS-II (Bharat Stage II):

Now talking about BS-II where a significant number of changes were made, Implemented in 2001, BS-II aimed to reduce emissions from vehicles further. The most significant change that the BS-II brought was the restriction of Sulphur to 500 ppm. This meant that the automakers were expected to get rid of the carburetor and adopt the multipoint fuel injection (MPFI) system. It also tightened the limits for CO, HC, and NOx emissions, contributing to a reduction in air pollution.

BS-III (Bharat Stage III):

Rolled out in 2005 for four-wheelers and in 2010 for two-wheelers, BS-III was a significant step forward. This stage of the BS emission norm was based on the Euro III emission norms. This stage dealt with more restrictions on the gases emitted by the vehicles and demanded a sulfur content of no more than 100 ppm. This stage also restricted the amount of nitrogen gas and the amounts were further reduced three times over the years. So, the automakers used catalytic converters to heavily reduce the emission levels of carbon monoxide and hydrocarbons.

This stage also introduced stricter emission standards, particularly for diesel vehicles.

It mandated the use of advanced emission control technologies such as catalytic converters for petrol vehicles and diesel particulate filters for diesel vehicles.

BS-IV (Bharat Stage IV):

BS-IV norms came into effect in 2010 in 13 major cities and were extended nationwide in 2017.

This stage focused on reducing sulfur content in diesel fuel, which helped decrease particulate matter (PM) emissions. It allowed no more than 50 ppm of sulphur. The automakers had to use bigger catalytic converters, make changes in the ECU for more efficient combustion, and also updated the air intakes and exhaust systems to make the engines run cleaner. It also set more stringent limits for CO, HC, NOx, and PM emissions for both petrol and diesel vehicles.

BS-V (Bharat Stage V) and BS-VI (Bharat Stage VI):

Originally, BS-V was scheduled for 2019 and BS-VI for 2023. However, the government decided to leapfrog from BS-IV to BS-VI directly to address the growing concerns about air quality.

BS-VI, the latest and most stringent stage, was implemented nationwide on April 1, 2020.

These norms significantly reduce emissions of NOx and PM from vehicles, aligning India with global emission standards. The sulphur level allowed in BS-VI is just 10 ppm which is a long way from the 500 ppm allowed in BS-II.

Differences Between Various BS Stages:

Emission Limits:

The permitted quantities of contaminants are one of the most important distinctions between BS stages. Each stage has imposed higher limitations on pollutants such as CO, HC, NOx, and PM, resulting in cleaner air.

Fuel Quality:

Fuel quality has improved in tandem with the growth of BS standards. Lower sulfur content in diesel fuel was specified by BS-IV and BS-VI, lowering PM emissions.

Technological Advancements:

To meet the stringent BS norms, vehicle manufacturers have had to adopt advanced emission control technologies. These include catalytic converters, selective catalytic reduction (SCR) systems, and exhaust gas recirculation (EGR) systems.

Implementation Timeline:

The implementation timeline for each BS stage has varied. While BS-I and BS-II were implemented relatively quickly, there were longer gaps between subsequent stages to allow manufacturers to adapt to the new standards.

Geographical Scope:

Initially, BS norms were implemented in major cities with high pollution levels. However, as awareness about air quality and environmental concerns grew, the scope expanded to cover the entire country.

Public Health Impact:

The impact of each BS stage on public health is significant. Stricter norms have led to a reduction in respiratory diseases and other health issues caused by air pollution.

Bharat Stage Emission Norms have played a pivotal role in reducing vehicular emissions and improving air quality in India. The evolution of these norms from BS-I to BS-VI reflects the government's commitment to environmental sustainability and public health. By setting increasingly stringent standards for vehicle emissions, India is making steady progress towards a cleaner and healthier future. It is essential for policymakers, vehicle manufacturers, and the public to continue their efforts to support and adhere to these emission norms to mitigate the adverse effects of vehicular pollution on the environment and human health.