What are major differences between the Bharat stage IV and Bharat stage VI? What would be possible impacts of SC verdict on upgrading to BSVI norms?

The Bharat Stage norms are standards set by the government to regulate emission of air pollutants from motor vehicles. The norms set the limit for the release of air pollutants such as nitrogen oxides, carbon monoxide, hydrocarbons, particulate matter (PM) and sulphur oxides from vehicles using internal combustion engines. The Bharat stage norms are based on Euro norms.

Difference between the Bharat Stage IV and Bharat Stage VI norms:

• The extent of sulphur is the major difference between the Bharat stage IV and Bharat stage VI norms.
• Bharat stage IV fuels contain 50 parts per million (ppm) sulphur where as Bharat Stage-VI grade fuel only has 10 ppm sulphur.
• Bharat Stage VI will bring PM in diesel cars down by 80 per cent when compared to Bharat stage IV.
• Bharat Stage VI will bring down nitrogen oxides from diesel cars by 70 per cent and in petrol cars by 25 per cent.

SC verdict on upgrading to BS VI norms:

• The Supreme Court has ruled that only Bharat Stage VI compliant vehicles can be sold in the country starting from April 2020.
• The Supreme Court said that the need of the hour was to move to a cleaner fuel.

Impact of the judgement:

• The oil refineries will need a substantial investment to upgrade to supply fuel types that can match the BS-VI standards.
• The shift is expected to cost anything between Rs 50,000 crore to Rs 80,000 crore to petroleum companies.
• The automobile manufacturers will be under extra pressure to produce compliant vehicles.