Bharat Stage (BS) Emission Norms

From CSE Wiki
  • Bharat Stage (BS) emission norms are standards to regulate the output of air pollutants from internal combustion engine equipment, including motor vehicles.
  • BS norms are based on European emission standards.
  • Central Pollution Control Board (CPCB) sets the standards and is responsible for the implementation of Bharat Stage Norms.


  • BS norms were introduced in 2000.
  • BS IV norms came into effect on 01 April 2017.
  • India is skipping BS V and will move directly to BS VI.
  • BS VI norms came into effect on 01 April 2020.
    • BS VI norms came into effect on 01 April 2018 in Delhi. (Due to heavy air pollution problem in Delhi)
    • BS VI norms came into effect on 01 April 2019 in NCR.

BS VI norms

  • BS VI norms are based on Euro 6 norms.
  • It cuts down permissible sulphur content in emissions to 10 parts per million (ppm) from 50 ppm (under BS IV). (Sulphur in the fuel contributes to fine particulate matter emissions. It also leads to corrosion and wear of the automobile engine.)
  • There is also a reduction in carbon monoxide, nitrous oxide, unburnt hydrocarbons and particulate matter standards.

Components required for BS VI vehicle

  • Selective Catalytic Reductor
  • Diesel Particulate Filter
  • Lean NOx trap


  • There are no CO2 norms in BS norms. (EU has standards on CO2 emissions)
  • BS norms lag behind Euro norms in implementation. (Euro 6 came into effect in 2015 whereas BS VI will come into effect in 2020)

Why India skipped BS V?

  • To accelerate the efforts in controlling air pollution.
  • There was little difference between Euro 5 and Euro 6 norms.