Sarat Chandra IAS Academy

UPSC Civils Daily Mains Question 25th April 2020

Q) According to a United Nation report “9 out of 10 people on the planet are breathing polluted air”. In this light discuss the role of Bharat Stage (BS)-VI standard vehicles in combating air pollution. What are the differences between BS-IV and BS-VI standard vehicles? What are the challenges associated in implementing BS-VI norms? Suggest measures for effective implementation of the BS-VI norms.


The Bharat Stage (BS) are emission standards instituted by the Government of India to regulate the output of air pollutants from motor vehicles. The Central Pollution Control Board is the implementing agency of these standards. About one-third of the air pollution is caused by cars and motor vehicles. With the implementation of BS-VI norms, pollution levels are expected to come down significantly as the particulate matter (PM) will decrease.

Role of BS-VI vehicles in combating air pollution:

  • BS-VI will reduce toxic substances in the air resulting in reduction of air pollution
  • Selective Catalytic Reduction Technology helps to reduce oxides of nitrogen by injecting an aqueous urea solution into the system.
  • The lower sulphur in BS VI will help reduce harmful exhaust emissions like NO2, CO, SO2.
  • For old vehicles, BS-VI standards open up an option of
  • The change in density of diesel oil will help to improve the quality of oil as well as help to reduce air pollution.
  • Early migration to BS-VI fuels will help in saving thousands of precious lives by bringing down vehicular pollution
  • Mandatory On-Board Diagnostics (OBD) will inform the vehicle owner or the repair technician about how efficient the systems in the vehicles are.
  • BS-VI norms are expected to reduce the PM 2.5, which are tiny particles in the air that reduce visibility and cause the air to appear hazy when levels are elevated.

Difference between BS-IV and BS- VI:

 The BS-VI emission standards are much more elaborate in their scope and integrate substantial changes to existing emission standards ensuring cleaner products to the consumer.

The major difference between the existing BS-IV and forthcoming BS-VI norms are:

BS IV vehicles

BS VI vehicles

Sulphur content in the fuel is high than BS- VI Sulphur content in the fuel is less than BS- IV
The emission of NOx (nitrogen oxides)from diesel and petrol cars are higher than BS-VI BS-VI vehicles will reduce NOx (nitrogen oxides) emission from diesel cars by 70% and from petrol cars by 25%
There is no RDE (Real Driving Emission) They have RDE (Real Driving Emission) that will measure the emission in real-world conditions and not just under test conditions
The particulate matter is measured by mass standard The particulate matter is measured by number standard instead of mass standard thereby, regulating the fine particulate matter as well.
The cost of producing BS IV grade fuels is less than BS-VI The cost of producing BS VI grade fuels is high
 carbureted engines are used in two wheelers fuel injection engine are used in two wheelers
The techniques for meeting gasoline fuel quality was no effective For meeting gasoline fuel quality, desulphurization technologies along with octane boosting units are being installed.


Challenges in BS-VI norms:

  • Adding BS-VI fuel in the current BS-IV engines (or conversely, running BS-VI engines on the current-grade fuel), may be both ineffective in curbing vehicular pollution, as well as damage the engine in the long run.
  • Stressed Industry: Automotive industries are already under pressure due to a decrease in the sale. With the introduction of BS-VI norms along with strict safety, norms may increase the cost of vehicles which might further pressurize the automotive industries.
  • Technological Challenges:
    • New technology will be required by the automotive industries in combustion, ignition, carburetors, and exhaust steel pipe.
    • Car-makers will have to spend heavily to develop BS-VI compliant engines for their existing product line.
    • Automotive electronics and embedded systems related constraints.
  • Low Incentive for the Buyer:
    • There is no improvement in fuel efficiency in the case of BS-VI vehicles, which was the selling pitch in the case of BS-IV vehicles.
    • Cost of maintenance of BS-VI vehicles is higher than the BS-IV vehicles.
  • Availability of the Fuel: To ensure the availability of BS-VI fuel at all places by the due time will be another problem faced by the Oil Marketing Companies.
  • Low Transparency: Transparency in fuel production and its transportation is absent.
  • Logistics Issues: implementation of BS-VI in the whole country at the same time which might lead to logistics issues.

Measures for effective implementation of BS-VI:

  • Cleaner fuel alone will not make a dramatic difference to air pollution. For the full benefits to be experienced, the introduction of the higher grade fuel must go hand in hand with the rollout of BS-VI compliant vehicles as well.
  • The proper business ecosystem including financing of vehicles should be made easy by increasing the tenure and thereby reducing the EMI.
  • The overall cost of the vehicle and the fuel must be streamlined by including petroleum in Good and Service Tax. Effective GST must be rolled back to ease the burden of the depressed automobile sector.
  • People must be given awareness to avoid the misconception about the new fuel and vehicles.
  • The vehicle should have the capacity to use the fuel at full combustion

The cleaner fuel emission control systems in the existing fleet can more optimally control toxic emissions. If BS-VI emission norms are implemented effectively, India will come at par with the US, European countries and other advanced automotive markets across the globe. These reforms can put India ahead in the race for investments too.

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