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Simply put: What needs to be done to upgrade from BS-IV

Four years from now, the government wants to leap directly to BS-VI auto emission norms from the existing BS-IV, skipping BS-V. But the challenges, before both oil companies and automakers, are enormous.

Written by Anil Sasi |
January 7, 2016 12:20:14 am
BS VI norms, india skips BS V, air pollution, BS VI curbs vehicular pollution, low vehicular pollution, bharat stage VI, BS VI emission norms, odd even scheme, delhi pollution BS-V requires a key fitment in the engine; BS-VI needs one more, but each comes with its set of problems.

The decision — announced by the government on Wednesday after a meeting of the Ministers for Road Transport, Petroleum, Heavy Industries, and Environment — to bring forward the nationwide rollout of BS-VI vehicular emission norms (Report, Page 21), is in line with promises made by India at the Climate Change Conference in Paris last month, and the broad public sentiment against the dangerously high levels of air pollution in major Indian cities, led by the national capital, New Delhi.

BS Emission Norms

The BS — or Bharat Stage — emission standards are norms instituted by the government to regulate the output of air pollutants from internal combustion engine equipment, including motor vehicles. India has been following the European (Euro) emission norms, though with a time lag of five years. BS-IV norms are currently applicable in 33 cities in which the required grade of fuel is available; the rest of India still conforms to BS-III standards.

India introduced emission norms first in 1991, and tightened them in 1996, when most vehicle manufacturers had to incorporate technology upgrades like catalytic converters to cut exhaust emissions. Fuel specifications based on environmental considerations were notified first in April 1996 — to be implemented by 2000, and incorporated in BIS 2000 standards. Following the landmark Supreme Court order of April 1999, the Centre notified Bharat Stage-I (BIS 2000) and Bharat Stage-II norms, broadly equivalent to Euro I and Euro II respectively. BS-II was for the NCR and other metros; BS-I for the rest of India.

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From April 2005, in line with the Auto Fuel Policy of 2003, BS-III and BS-II fuel quality norms came into existence for 13 major cities, and for the rest of the country respectively. Subsequently, BS-IV and BS-III fuel quality norms were introduced from April 2010 in 13 major cities and the rest of India respectively.

As per the roadmap in the auto fuel policy, BS­V and BS-VI norms were to be implemented from April 1, 2022, and April 1, 2024, respectively. But in November 2015, the Ministry of Road Transport issued a draft notification, advancing the implementation of BS­V norms for new four-wheel vehicle models to April 1, 2019, and for existing models to April 1, 2020. The corresponding dates for BS-VI norms were brought forward to April 1, 2021, and April 1, 2022, respectively.

But the government’s “unanimous decision to leap-frog to BS-VI directly from 01/04/2020”, as Road Transport & Highways Minister Nitin Gadkari announced on Twitter on Wednesday, skipped the BS-V stage all together.

CaptureThe Challenges

The government could face two key challenges in implementing the decision. First, there are questions about the ability of oil marketing companies to quickly upgrade fuel quality from BS-III and BS-IV standards to BS-VI, which is likely to cost upwards of Rs 40,000 crore. Second, and more challenging, is the task of getting auto firms to make the leap. Automakers have clearly said that going to BS-VI directly would leave them with not enough time to design changes in their vehicles, considering that two critical components — diesel particulate filter and selective catalytic reduction module — would have to be adapted to India’s peculiar conditions, where running speeds are much lower than in Europe or the US.


These challenges are very real — note that the penetration of BS-IV motor spirit (petrol) in the domestic market a full four years after its introduction in the metros, was just about 24 per cent, and that of BS-IV high speed diesel only 16 per cent, according to government data up to August 2014.

Also, the rollout model of introducing higher grade fuel and vehicles first in the cities has fundamental drawbacks, as was evident in the BS-IV implementation. In the periphery of designated BS-IV cities, BS-III vehicles could be registered; BS-IV vehicles (especially heavy vehicles) were more expensive, and BS-III fuel was cheaper than the BS-IV equivalent. And interstate trucks and buses, the biggest polluters, were forced to stay on with BS-III engines simply because the fuel outside cities did not conform to BS-IV norms.

Fuel Quality, Costs

The government has been unable to move completely to BS-IV because refiners have been unable to produce the superior fuel in the required quantities. BS-IV petrol and diesel essentially contains less sulphur, a major air pollutant. Sulphur also lowers the efficiency of catalytic converters, which control emissions.


Broadly, BS-IV petrol and diesel have 50 parts per million (ppm) of sulphur, as compared to 150 ppm for petrol and 350 ppm for diesel under BS-III standards. Oil companies are learnt to have put in Rs 30,000 crore between 2005 and 2010 to upgrade; the auto industry has made investments of a similar size. Oil firms will have to invest another about Rs 40,000 crore to upgrade fuel quality to BS-VI; additional investments by automakers to upgrade will inevitably raise the prices of vehicles.

Industry Arguments

The auto industry argues that the huge improvements in vehicular technology since 2000 have had little impact in India due to Indian driving, road and ambient conditions. The technology that will be used in future BS-VI vehicles, though, will have considerable impact, they claim. BS-V diesel vehicles were to have engine upgrades, particulate filters, lots of sensors, and electronic control. Petrols were to have catalyst and electronic control upgrades. Industry estimates of required investment to upgrade from BS-IV to BS-V are to the tune of Rs 50,000 crore. Vehicles must be fitted with DPF (diesel particulate filter), a cylindrical object mounted vertically inside the engine compartment. In India, where small cars are preferred, fitting DPF in the limited bonnet space would involve major design and re-engineering work. Bonnet length may have to be increased, which would make vehicles longer than 4 metres, and attract more excise duty under existing norms.

Also, DPF would have to be optimised for Indian conditions. The technology available in Europe can’t be used in plug-and-play mode, claim auto majors. Low driving speeds in India would make it difficult to achieve temperatures of 600 degrees Celsius required to burn the soot in DPF, and equipment manufacturers would have to work with temperatures of 400 degrees in sight. Usually, diesel is injected to increase temperatures, but the accumulation of excess fuel in the compartment can cause a fire. The injection rate has to be optimised and vehicles re-engineered for safety. The integrity of the vehicle too has to be considered. This would require validation tests over 600,000-700,000 km — a process that may take up to four years.

BS-VI vehicles also have to be equipped with an SCR (selective catalytic reduction) module to reduce oxides of nitrogen, which is done by injecting an aqueous urea solution (AUS 32, which contains ammonia) into the system when the exhaust is moving. For this, a container needs to be put on board; also, an anti-defect mechanism has to be devised, so that the vehicle goes into limp mode if AUS 32 is not re-filled by the driver. Infrastructure needs to be set up across the country for the supply of AUS 32. The optimisation and fitment of this technology too would take an estimated 3-4 years.

At every stage, the technology is getting more complex. To attain the specified super low emissions, all reactions have to be precise, and controlled by microprocessors. If BS-V were to be skipped entirely, then both DPF and SCR would need to be fitted together for testing, which, auto firms say, would make it extremely difficult to detect which of the technologies is at fault in case of errors in the system. Ideally, the technologies must be introduced in series, and then synergised. So, even if oil companies manage to leap, auto firms claim they need 6-7 years to switch to BS-VI.

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First published on: 07-01-2016 at 12:20:14 am
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