Bharat Stage Emission Norms explained: How much cleaner are BS6 vehicles?
BS emission norms restrict the amount of gases expelled by an IC engine while it is

Bharat Stage Emission Norms explained: How much cleaner are BS6 vehicles?

India’s journey from 2000 emission norms to the BS-VI emission norms has been quite a long one

Ever wondered what is the deal with the BS compliance in the auto sector? Well worry not, we at evo India will give you a brief introduction to the BS emission norms. BS stands for Bharat Stage and are the emission norms followed by the auto manufacturers, regulated by the Government of India in order to control the output of pollutants expelled by Internal Combustion Engine (ICE) vehicles into the air. These emission norms are based on the Euro standard emission norms and are updated regularly to make vehicles more environmentally friendly and greener.

The current emission norm in India is BS-VI which came into play across the country on April 1 2020, based on the Euro 6 vehicle emission standards. The standards basically dictate the amount of gases a vehicle is allowed to emit. More specifically, gasses like carbon dioxide (CO2), carbon monoxide (CO), Hydrocarbons and oxides of Nitrogen, which are the byproducts of an IC engine running.

India 2000 (BS I emission norms) 2000

To talk about what these emission norms allow and restrict, we first need to know a little history of the norms in India. The BS-I or the India 2000 emission norms was launched in the year, no prize for guessing, 2000. India 2000 was based on the Euro I emission standards and the automakers were to comply with the emission norms starting April 1, 2000. To comply with these norms the automakers made changes and adopted catalytic converters to convert the toxic gases into less harmful emissions, for example, CO would be converted to Co2. Plenty of auto manufacturers were not prepared to adopt these standards immediately, some manufacturers had to even stop/pause the production of their petrol vehicles at the time, although it was relatively easier for the diesel vehicles to comply with the norms.

BS-II emission norms (started 2001)

Moving to BS-II where major changes started happening, The Stage Two emission norms came into application just after a year in a few cities, namely Delhi NCR, Mumbai, Kolkata and Chennai. The Stage Two emission norms became nationwide by the year 2005. The major change in Stage Two was bringing in restrictions for Sulphur to 500ppm. The automakers were expected to get rid of the carburettor and adopt the multi-point fuel injection (MPFI) system, which many automakers were not prepared to incorporate and thus it took longer for the Stage Two norms to go nationwide.

BS III emission norms (started 2005)

The Stage Three emission norms were based on the Euro III emission norms, and although initiated in 2005, was made mandatory nationwide only in the year 2010. Stage Three dealt with more restrictions on the gasses emitted by the vehicles and demanded a sulphur content of no more than 100ppm. Stage Three also restricted the amount of nitrogen gas and the amounts were further reduced three times over the years. Automakers used catalytic converters to heavily reduce the emission levels of carbon monoxide and Hydrocarbons.

BS IV emission norms (started 2010)

The Stage Four emission norms were made mandatory first in the year 2010 in select few cities and were made nationwide by the year 2017. The emission levels of the pollutants level were heavily reduced in Stage Four and it allowed no more than 50ppm of sulphur. Major changes were incorporated by auto manufacturers to comply with the stricter emission norms — 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.

BS-VI emission norms (started 2017)

Yes, we skipped the BS V emissions norms, thanks to the fact that the European emission norms were already on Stage Six and the alarming levels of pollution demanded the shift to stricter emission norms. The Stage Six emission norms were made mandatory nationwide in the year 2020, not long after the BS-IV came fully into action. The Sulphur level allowed in BS-VI is just 10ppm which is a long way from the 500ppm allowed in BS-II.

The environmental impact that these gases had on the environment was lethal and the drastic reduction in the same points towards a sustainable and greener future. With alternative fuels starting to make noise in the auto industry, major auto manufacturers have decided to go green with electric power, hydrogen fuel cells and incorporating ethanol for cleaner emissions. It will be interesting to see what happens next in the auto industry regarding emission norms.

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