Shadow of Dieselgate: alarmingly high emissions from diesel cars, SUVs on Indian roads

The first ever real world emissions testing of BSIV cars in India shows alarmingly high real world emission from diesel cars on road, explodes clean diesel myth

By Anumita Roychowdhury
Published: Friday 11 August 2017
Controlling on-road emissions from diesel vehicles is more complex and expensive than petrol vehicles. Credit: Samrat Mukherjee / CSE
Controlling on-road emissions from diesel vehicles is more complex and expensive than petrol vehicles. Credit: Samrat Mukherjee / CSE Controlling on-road emissions from diesel vehicles is more complex and expensive than petrol vehicles. Credit: Samrat Mukherjee / CSE

India thought it could turn a Nelson eye towards dieselgate that has gripped dieselised Europe. That this could be easily dismissed as somebody else’s problem and stay complacent about its own diesel mania. Worse, it thought it could also disregard its homegrown concerns around higher toxic emissions from diesel vehicles. No more. The stunning results from real-world emissions testing in Indian cars by the International Centre for Automotive Technology (ICAT), the Indian vehicle testing agency, and International Council on Clean Transportation (ICCT)—the same group that had exposed the Volkswagen scandal in the US—show Indian diesel cars are as deviant. This first ever real-world emission testing study rocks the myth of clean diesel cars spawned by the auto industry.

This joint study has tested Bharat Stage IV (BSIV) compliant 2015 model of petrol car (Hyundai i20), diesel car (Hyundai i20diesel), and diesel SUV (Mahindra XUV500 W8). These cars were tested first in the laboratory the same way as vehicle certification. Thereafter, portable emission monitoring equipment was mounted on them to measure gaseous emission while being driven through city roads and highway close to Delhi. For on-road testing, the study followed requirements of the European real driving emissions requirement with specific urban, rural and highway traffic conditions and requisite speeds. But same vehicles were also driven as they would normally do on roads and their real world emissions were monitored. This kind of real world emissions monitoring has already been provided for in the Bharat Stage VI emissions (BSVI) standards in India.  

Lab test: Emissions from on-road diesel cars far exceed BSIV standards

When both petrol and diesel cars and SUVs were put through lab test, the end result reaffirmed what we know from Europe. Nitrogen oxide (NOx) emission from petrol car is well below emissions standard of BSIV; but much higher from diesel car. More worrying is very high numbers of extremely tiny particles bordering on the ultrafine range from diesel cars and SUVs. BSIV diesel cars have at least a 1000 times the number of smaller ultrafine particles that would be present in a well designed BSVI vehicle. This shows how urgently India needs to move to diesel particulate filter that will come with BSVI norms and also control dieselisation.

Real world emissions from diesel cars and SUVs alarming

Same cars were brought out of the lab and were driven on the road to test for real-world gaseous emissions with portable monitors. The results from diesel car and SUV are alarming. Real world NOx emissions from small Hyundai i20 diesel are three—six times the standard but a whooping 9 to12 times the Hyundai i20 petrol NOx levels. As expected, NOx emissions from petrol car are much lower—about 0.5-0.7 times the BSIV standard.

SUVs are far worse. Real-world NOx emissions from diesel SUV are 4-6 times higher than its already weak NOx standard which, in turn, is 5 times higher than the petrol NOx standard. Thus, NOx emissions from Mahindra’s XUV diesel SUV are 25 to 65 times higher than the i20 petrol NOx emissions level. This virtually means that in terms of NOx emissions, adding one XUV diesel SUV to the city’s car fleet is equal to adding 25 to 65 small petrol cars.

Source: Laboratory and On-Road Emission Testing of In-use Passenger Vehicles in India, ICAT and ICCT, 2017

Average test results shown above the bars. Error bars show one standard deviation of test results

There are several messages here. “This study confirms diesels pollute much more on road compared with petrol, and that larger diesels (SUVs etc) are even more polluting. Not only does India needs to adopt tighter test procedures and new driving cycle for certification of vehicles as soon as possible, it also needs to adopt real world driving emissions testing for both type approval and for in-use compliance purposes,” says Anup Bandivadekar of ICCT who was part of the research team.

On-board diagnostic system fails to diagnose emissions anomalies

This study has also found that the on-board diagnostic system (OBD)—the self policing system in cars— is not designed or capable of detecting whole range of emissions anomalies. After the introduction of BSIV emissions standards, a lot of investments have been made by the car companies to install on OBD system in cars to record any defect or anomaly. But this study has exposed that the OBD in Bharat IV diesel cars is unable to detect problems with several aspects of emissions control system. For instance, in BS IV vehicles in India, in-cylinder NOx emissions are controlled by using cooled exhaust gas recirculation (EGR) system and particulate matter is usually controlled by using a diesel oxidation catalyst. The test has found a mechanical failure (punctured rubber hose) in the EGR in diesel cars that has resulted in three times more emissions than the fixed limit. But the OBD systems are not even designed to identify this failure that has significant impact on emissions. The specifications for on-board diagnostics need to be extended and tightened substantially.

Why Indian BSIV diesel cars are high NOx emitters?

Just as seen in Europe with more advanced diesel cars, similar trend in high on-road NOx emissions from BSIV diesel cars is evident in India. Researchers suggest that it is a possibility that the BS IV vehicles in India, that have weak emissions control systems, are being tuned for lower particulate matter emissions from the engine but higher NOx emissions while boosting fuel efficiency. This tradeoff is leading to higher NOx emissions. Clearly, the problem in Europe and India is that the emissions standards for NOx are more lax for diesel cars and SUVs than for petrol cars, especially under the BSIII and BSIV regulation. This leads to significantly high NOx emissions. The obstinately rising ambient NOx levels in Indian cities are already worrying.

But India must also watch and draw lessons from diesel gate unfolding in Europe and understand the reasons for high on-road NOx emissions from Euro VI diesel vehicles as well. The ICCT review of European situation reveals that the new systems to control NOx in Euro V and Euro VI diesel vehicles are vulnerable to cheating and sub-optimal performance on roads. The selective catalytic reduction (SCR) technology in the exhaust system injects automotive grade urea in the exhaust. This reacts with the NOx in the exhaust gases to reduce it. This urea is consumed in proportion to NOx emissions from the engine.

Manufacturers in Europe have designed engines that operate under two different urea consumption modes: one highly consuming when tested in the laboratory and one that consumes much less for on-road operation. As urea has a cost, manufacturers may try to show their vehicle consume very little urea, to make it attractive for consumers. But the real driving conditions demand more robust SCR operation and that makes it more expensive. The manufacturers are designing these systems for NOX control for compliance in the laboratory, making the systems cheaper. Some added software that identifies when vehicle is being tested and when on road so that the emissions control system adapts to each condition. This problem can be countered with real-world testing with portable emissions systems.

Way back in 2011, Europe had decided to add real-world emissions testing as part of the certification process for diesel cars—even before dieselgate. After dieselgate exploded, the European regulators accelerated the implementation of the real-world testing and have changed the regulation to correct both high emissions and avoid manufacturer cheating.

Experts advise that India should adopt strong real-world emissions testing with portable emission systems. It is said that even the traditional fuel efficiency benefit of diesel engines with respect to petrol ones is vanishing with the adoption of gasoline direct injection (GDI) and other advanced combustion technologies. India needs to ensure vehicles emit as little as designed by the standard, independent of fuel, and that the good performance in the laboratory also translates to good performance on the road, regardless of the driving habits and conditions of India.

What is at stake?

Indian automobile industry is weary of real-world emissions monitoring with portable emissions monitors for compliance that is being implemented in Europe in response to diesel gate. Anticipating similar problems with diesel cars in India, the Indian automobile industry is resisting the idea. They want to substitute real-world emission testing for in-use compliance with a lab test claiming that this can nearly mimic all real driving conditions. Industry is raising doubts about reliability of portable monitoring machines, its appropriateness for Indian conditions and claiming regulatory uncertainty over these tests in Europe to block the move.  

But European Union has already implemented real driving emissions testing using portable monitors and the regulation is already out. All manufacturers, offering vehicle to the European market, have to fulfil these requirements for new vehicles.

Francisco Prosada of ICCT, one of the lead researchers of this new study in India, says, “Tests on all vehicles were carried out with the same portable emissions testing system, by the same testing team, on same driving routes; and were exposed to the same test variability: variable traffic conditions, road grade variations, and so on. Despite the variability, the results for the i20 Petrol are consistently below the BSIV standard. The problem is the diesel vehicle emission control system.”

Clearly, controlling on-road emissions from diesel vehicles is more complex and expensive than petrol vehicles. Portable monitors are not the issue. As global experience and particularly, the Volkswagen scandal shows, laboratory testing can be easily compromised. Portable monitoring of real-world emissions are the only way to ensure robust emissions control systems, prevent industry cheating and stop use of defeat devices. 

India must quicken its steps to develop portable emissions monitoring of real-world driving emissions. China has already started it in multiple cities using China VI calibrated vehicles, informs Michael Walsh, who is advising the Chinese government on vehicular emissions control. India should do the same to generate some real data.

Backlash in Europe

India cannot ignore that there is serious backlash against diesel cars in Europe. Reports are pouring in on how European cities are gearing up to ban, or restrict or tax diesel cars. Paris has banned pre-1997 diesel vehicles and is now extending the ban to pre-2001 diesel vehicles this year. London is creating an ultralow-emission zone with high road tolls. Oslo enforced diesel ban and fined violators during winter. Stuttgart will ban all except most modern diesels. Munich is framing a plan in response to a court ruling. Mexico City, Athens and Madrid have pledged to ban all diesel vehicles from their cities by 2025. Seoul plans to ban diesel made before 2006 from driving in the city’s central districts. Less than 5 per cent of the US cars are diesels, compared to half in Europe.

Accept and Act

It’s a reality in India that the car market is beginning to feel the heat of environmental and public health concerns around toxic diesel. Recent reports show that the Minister of State for Heavy Industries in a written reply in Parliament has stated that sales of diesel cars has plummeted to 27 per cent, from 47 per cent  in 2012-13, indicating that diesel cars may be on the way out. The data on fuel-wise sales percentage in domestic sales placed in Parliament shows that the percentage of diesel cars sold in India is consistently declining since 2012-13, largely due to recent action like the recent ban by the National Green Tribunal on diesel cars of more than 10 years old. However, despite this overall decline, growth rate of SUVs has remained very high. This month, SUVs have clocked 35 per cent increase compared with the corresponding period last year.  

Given the very high level of pollution in Indian cities, the public health risks are very high. While overall particulate levels remain a strong concern, newer concern around NOx and ozone and ultrafine particle is growing. India must control dieselisation and be better prepared for implementation of BSVI emissions standards in 2020 to make advanced technologies to deliver on intended objective. Now there is data to prove the threat.

“The regulators will have to impose on the manufacturer a reasonable expectation of good real-world emissions performance, and make on-road performance of diesels cars improve to the level of petrol cars. If regulators fail to do this the citizens will have to pay a high health cost for non-compliance. This burden should be borne by a handful of manufacturers, and not by a billion people. The choice is not technical, it is moral,” adds Prosada. 

Signs are grave and worrying. India must not re-enact the dieselgate.

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