Bharat Stage Emission Norms: BS-I, BS-II, BS-III, BS-IV, BS-VI Explained

As environment conservation comes under greater focus globally, pollution from our vehicles has become a key area for stricter regulation. These regulations are formalized in the form of emission norms. Emission norms simply mean government-mandated limitations for the level of pollutants emitted by automobiles. To keep our vehicles’ pollution output in check, like other governments around the globe, the Central Pollution Control Board (CPCB) under the Ministry of Environment, Forest and Climate Change (MoEF&CC), has Bharat Stage Emission Norms enforced across India. First enforced in the year 2000, the Bharat Stage Emission Norms are based on the European Emission Standards (Euro norms) and are updated from time to time to promote a greener lifestyle. In this article, we explore all the Bharat Stage Emission Norms that were enforced, are currently in place, and are expected to be enforced in India.

What is BS-I?

The BS-I norms were called ‘India 2000.’ Enforced in the year 2000, the India 2000 were the first set of Bharat Stage Norms and based on the Euro I emission standards. The automobile manufactures were to comply with the India 2000 norms from April 1, 2000. Following are the India 2000 norms.

What is BS-II?

The Bharat Stage Two norms or BS-II norms were first implemented in 2001. But at the time it was limited to metropolitan cities such as Delhi NCR, Mumbai, Kolkata, and Chennai. The BS-II was enforced nationwide in 2005. While there were some updates in the norms, a major one was putting restrictions on Sulphur emissions, which now were limited to 500 ppm. Moreover, the automakers were encouraged to adopt the multi-point fuel injection system (MPFI) and quit using carburettors. Many automakers faced many challenges to do so and that is why the government took a long time to enforce the BS-II nationwide.

What is BS-III?

In 2005, the Bharat Stage-III norms were implemented in major cities like the Delhi NCR, Mumbai, Kolkata, Chennai, Bangalore, Hyderabad including Secunderabad, Ahmedabad, Pune, Surat, Kanpur, and Agra.  Then, in 2010, it was enforced nationwide. With the Bharat Stage III norms, the government increased restrictions on gaseous emissions such as Nitrogen Oxides, Carbon monoxide, and Hydrocarbons. Moreover, it limited the sulphur content to no more than 100 ppm.

What is BS-IV?

In 2010, when the Bharat Stage III norms were enforced nationwide, the Central Pollution Control Board enforced Bharat Stage IV in thirteen major cities – Delhi national capital region, Mumbai, Kolkata, Chennai, Bangalore, Hyderabad, Ahmedabad, Pune, Surat, Kanpur, Agra, Solapur, and Lucknow. Then by 2017, these norms were made mandatory nationwide. Much stricter than the earlier norms, the BS IV norms reduced the limits for pollutants extensively and the Sulphur output was not allowed more than 50 ppm. Consequently, manufacturers made major changes in their engineering mechanisms; the catalytic converters which convert the toxic gases into less harmful emissions, were made bigger. The ECUs (electronic control units), some of the key components of automobiles, were recalibrated for more efficient combustions. Many such steps were taken by manufacturers.

What is BS-VI?

Since the Bharat Stage IV took a long time to be enforced across the nation, CPCB skipped the Bharat Stage V and directly enforced the Bharat Stage VI. The BS VI norms were first enforced in Delhi in 2018, then in the national capital region in 2019, and thereafter nationwide in 2020. In BS VI norms, updates have been made to the engine specification requirements as well as the fuel quality, making the fuel more refined. For BS VI norms, the Sulphur content is limited to 10 ppm, which is a huge reduction from the 500 ppm allowed in BS II.

What is BS-VII?

In 2023, Minister of Road Transport and Highways of India, Nitin Gadkari advised the carmakers to begin preparations for the adoption of Bharat Stage VII norms, which are expected to be enforced in near future. Like all BS norms, the BS VII norms will be based on Euro standards. Considering the European Commission’s announcements, the Euro Seven norms are expected to be deployed from 1st July 2025.

Expectedly, the BS VII norms will introduce stricter controls on the emissions from both petrol and diesel vehicles. A key feature in these new norms will be the ‘On Board Monitoring’ (OBM) that will monitor the tailpipe emissions in real time. This system will have to be installed in cars and along with the engine and exhaust gases, this system will monitor the emissions of Nitrogen oxides, Ammonia, and Particulate matter. Moreover, there will be additional rules for particulate emissions from brakes and microplastic emissions from tyres, which will be applicable to EVs as well.

Therefore, to comply with the BS VII norms, automakers will have to make significant technological advancements and investments to make more advanced pollution control systems and components. This will eventually result in higher manufacturing cost and then higher car prices for Indian consumers.

Summary

Over the years, the Bharat Stage Emission Norms have done a great job of keeping air pollution in check, especially in a country as large as India. First enforced in the year 2000, the Bharat Stage Emission Norms have been updated five times so far and become stricter each time. The upcoming BS VII norms will be even stricter and are expected to increase the cost of manufacturing cars. This will increase the cost of cars for the consumers as well.

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