BS-VI emission norms for vehicles: So near and yet so far, here is why

BS-VI emission norms for vehicles: So near and yet so far, here is why


Recently, the Union Petroleum Ministry decided to advance the introduction of BS-IV grade petrol and diesel in Delhi by two years to April 2018 in order to fight against air pollution.


  • The attempt was to leapfrog one stage-BS-V- altogether, and makes the switch to BS-VI that much more difficult for both the oil companies and automobile makers.
  • This is the second time that the government has shifted the goalposts — in January 2016, it had decided to skip BS-V and go directly to BS-VI, but only by 2020.

What is BS?

  • BS stands for Bharat Stage and is set by the central pollution control board. BS standard is generally applicable to all the vehicles that are running in the country.
  • BS is the emission standards given by Government of India to regulate the air pollutants coming from internal combustion engine.

What is BS-4?

  • BS-4 is regulation for everything that is emitted from vehicle.
  • The regulations not only cover exhaust emission but for evaporation emission, light emission, noise emission, tyre gas emission and perhaps a few more.

What is the significance of BS-4 fuel?

  • BS-IV fuels contain far less sulphur than BS-III fuel. Sulphur in fuel makes it dirtier and lowers the efficiency of catalytic converters, which control emissions.
  • The BS-IV compliant vehicles release less pollutants Carbon Mono-oxide (CO), Hydrocarbon (HC), Oxides of Nitrogen (NO), Sulphur (SO) and particulate matter (PM) compared to BS III compliant vehicles.
  • BS4 demands for lower limits of air pollutants like oxides of nitrogen, carbon monoxide, hydrocarbons and particulate matter, lower decibel of idle and pass, lower release of fuel vapour in atmosphere.

Reasons for shift:

The current BS-VI fuel in the current BS-VI engines, or running BS-VI engines on the current-grade fuel, may be ineffective in curbing vehicles pollution, and may damage the engine in the long run.

What is the significance of BS-6 fuel?

  • The proposed BS-VI fuel limits the amount of sulphur to 10ppm from 50ppm in BS-IV.
  • The fuel specifications of petrol and diesel have been aligned with the Corresponding European Fuel Specifications for meeting the Euro II, Euro III and Euro IV emission norms.
  • The introduction of BS-VI fuels in NCT by April 2018 will also give auto firms opportunities to market-test their models before the pan-India rollout happens in April 2020.

Difference between BS-IV and BS-VI:

  • The main difference between BS-IV and BS-VI (Which is comparable to Euro 6) is in the amount of sulphur in the fuel.
  • BS-VI fuel is estimated to bring around an 80% reduction in sulphur content –from 50 parts per million (ppm) to 10 ppm.
  • According to analysts, NOx emissions from diesel cars are expected to come down by nearly 70% and, from cars with petrol engines, by 25%.

Big hurdle :

  • For automakers, the big hurdle in jumping directly from BS-IV to BS-VI norms lies in equipping cars with two key fitments, and road-testing them within the same the time schedule.
  • Implementation of the intermediate BS-V standard was originally set to come in by 2024, was advanced by four years, in line with India’s promises at the 2015 Paris Climate Change Conference.
  • Automakers insist that BS-VI norms may not bring perceptible change in air quality but may increase the prices of vehicles and that it will be a challenge to upgrade technologies to meet the higher norms in the time available.

Emission norms:

  • The BS — Bharat Stage — emission standards are norms instituted by the government to regulate the output of air pollutants from internal combustion engine equipment, including motor vehicles.
  • India has been following European (Euro) emission norms, although with a time lag of five years.
  • India introduced emission norms first in 1991, and tightened them in 1996, when most vehicle manufacturers had to incorporate technology upgrades like catalytic converters to cut exhaust emissions.
  • Fuel specifications based on environmental considerations were notified first in April 1996 — to be implemented by 2000, and incorporated in BIS 2000 standards.
  • Following the landmark Supreme Court order of April 1999, the Centre notified Bharat Stage-I (BIS 2000) and Bharat Stage-II norms, broadly equivalent to Euro I and Euro II respectively.
  • BS-II was for the National Capital Region and other metros; BS-I for the rest of India.
  • From April 2005, in line with the Auto Fuel Policy of 2003, BS-III and BS-II fuel quality norms came into existence for 13 major cities, and for the rest of the country respectively.
  • From April 2010, BS-IV and BS-III norms were put in place in 13 major cities and the rest of India respectively.
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