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Rajya Sabha TV In Depth – BS-VI: Fuel in 6th Gear

Rajya Sabha TV In Depth – BS-VI: Fuel in 6th Gear


India today, is home to one of the most polluted cities in the world. For example, the air quality in its national capital Delhi is six times more dangerous than prescribed by the World Health Organisation. Delhi has thus, switched from Delhi has switched from Euro-IV grade to Euro-VI petrol and diesel which contains lesser sulphur and implies lesser pollution.



  • Delhi has become first city in India to sell the cleanest fuel in world BS VI on 01.04.2018. two years ahead of its deadline. It is the fuel equivalent to Euro 6 emission norms. It is a pro-active move of the government showing its willingness to achieve the target of switching to cleaner fuel.
  • Cities neighbouring Delhi and 30 major cities including Mumbai, Chennai, Bengaluru, Mumbai and Pune will also switch over to the BS VI-fuel from 1st Jan 2019. In the rest of the country it is planned to be rolled out from April 2020.
  • The move has cost thousands of crores rupees to refinery companies like Indian Oil for its fuel upgradation. The automobile companies will also have to bear the cost to improve their engines and for additions like oxygen sensors, selective catalytic reduction and particulate filters to improve to BS VI standard that will become mandatory by 1st April 2020.
  • Refineries need to put up diesel hydro-treating units, desulphurisation tech and octane boosting units to shift to BS VI. Indian refineries are investing 30,000 crore rupees to upgrade the technology.
  • Use of BS VI fuel increases fuel efficiency, improves combustion (chemical reaction between fuel and an oxidant) and reduces emissions.
  • Advantages of using BS VI fuel lie in the reduction of pollution emissions:
  1. Sulphur will be down from current BS IV level. BS VI = 10 ppm Sulphur and BS IV = 50 ppm Sulphur (ppm = parts per million)
  2. Particulate matter (sum of all solid and liquid particles suspended in air) will be reduced from 0.005 g/km as against 0.025 g/km of BS IV standard.
  3. Emission of Nitrogen Oxide (NOx) will be 70% less.
  • Bharat Stage Emission Standards (BSES) are emission standards instituted by Government of India. They regulate the output of pollutants from Internal combustion engines and spark-ignition engines, including motor vehicles.
  • The fuel standards are decided in India by Environment Ministry and their implementation is managed by Central Pollution Control Board.
  • According to international standards, PM 2.5 should not exceed 60 microgram/m3 in air. But, Delhi’s PM 2.5 levels are 10 times higher.
  • Burning of any fossil fuel creates pollution. So, either the vehicles should be changed to other types like electric vehicles or else, the fuel which is being burnt shall be made cleaner.
  • Increasing air pollution causes diseases like Asthma, Bronchitis, heart disease, etc. NOx when mixed Hydrocarbons in the atmosphere make the air poisonous.
  • Earlier Lead, being a slippery metal, was added for lubrication requirements in engines. But, in 1990s it was removed and refineries added certain additives in its place as use of lead was not safe.
  • After introduction of unleaded petrol in 1990s, due to economic liberalisation, the number of vehicles increased at a large rate. In 1999, the Supreme Court ruled that all vehicles in India have to meet Euro I or India 2000 norms. Then, by 2004-05 Euro 2 norms were implemented all over the country. Starting from 2005 in Delhi, Euro 3 norms were implemented all over the country by 2010. Finally, BS 4 standards were implemented in Delhi and 13 cities in 2010 and they were in force over the country by 2017.


Starting from use of lead in petrol, India has moved forward to unleaded petrol and then subsequently increasing its BS norms to BS 4. Seeing the poor Air Quality Index of Delhi, the early implementation of BS 6 in the region is a welcome step and it shall soon be implemented all over the country. To keep the rising air pollution in its cities alternative to cleaning the fuels and research on switching to other modes like electric vehicles need to be kept on track.