New Delhi, September 5, 2003: The Union ministry of road transport and highways has recently issued the draft notification on revised in-use vehicle emissions norms for the pollution under control certificate (PUC) scheme. The Centre for Science and Environment (CSE) is shocked that this first ever revision since the beginning of the programme in 1992 has not even addressed on-road diesel emissions -- source of the deadliest particles in our air. Neither has the notification laid out test procedures for all types of vehicles adequately to plug loopholes for manipulation and to validate the correctness of emissions tests.

While the roadmap proposed by the ministry is extremely weak, in the face of a consistent public campaign, it has made a vital concession: it has allowed state governments to set tighter norms if they wish. The onus now – therefore -- has shifted to the states to improve their vehicle inspection programmes.

Diesel vehicles get away
The new draft notification is completely silent on diesel vehicles and maintains a status quo in this regard. It does not modify the standards, nor the current test procedures. The government has been well aware of the shortcomings of the free acceleration smoke tests for diesel vehicles, but has chosen not to act on this knowledge.

For an accurate test, smoke density reading should be taken after rapid acceleration to full throttle. It is very easy to circumvent this test by not pressing the accelerator rapidly and fully. Ways to prevent this and to validate the test is to mandate additional measurements of speed of the engine and temperature of the engine oil at the time of testing. While engine speed can indicate consistency of tests, the oil temperature can say how well the engine has been warmed up to get the correct reading. The Union ministry, however, willfully ignores these requirements and fails to explain why the current smoke limit must not change for new vehicles on road.

CSE, based on its independent technical evaluation of the PUC programme in Delhi in March this year, has pointed out that the free acceleration smoke tests for diesel vehicles have very limited use in checking particulate emissions. A smoke test can catch only visibly smoking vehicles with malfunctioning engines, but not the vehicles with high emissions of finer particles, the main public health concern. CSE believes the current smoke test should be scrapped as soon as possible; till the time that happens, loopholes in the smoke tests procedures should be plugged in no uncertain terms. But the Union ministry is not willing to do that either.

This reprieve for diesel is a serious concern, as very few immediate emission control strategies exist for millions of diesel trucks, commercial vehicles, and diesel cars on road. Studies worldwide now point at the poor correlation between smoke and particulate emissions. Particulate measurements are possible only with loaded test procedures on a dynamometer – a treadmill kind of device used to simulate driving speeds on roads to measure emissions. Taking advantage of its new powers to set tighter standards, cities like Delhi should move in this direction as soon as possible.

Petrol norms: Will they make any difference?
While diesel vehicles have been let off, hesitant steps have been taken to improve petrol/CNG norms. Current carbon monoxide (CO) norms have become tighter and hydrocarbon (HC) norms have been introduced for the first time for new cars and two/three-wheelers. Separate norms have been introduced for new two-stroke and four-stroke-powered two/three-wheelers.

Are these adequate? Normally, in any typical vehicle inspection programme the norms are set to target the worst polluters -- around 20 per cent of the population -- at a time. But in India, the government does not release data on average emissions levels of the old and new fleets on road, to indicate the size fraction of vehicles that the new norms are targeting to reject. The proposed norms could be targeting much less than 20 per cent without any significant impact on overall emissions in most cities.

The proposed hydrocarbon norms of 1,500 ppm for old cars without catalytic converters, and, 750 ppm for Euro II compliant cars with three-way catalytic converters appear to be too lenient to fail any car. Even the little local information that is available casts doubt on the effectiveness of these norms. A small example from a survey conducted by the Automotive Research Association of India, the premier vehicle testing agency based in Pune, indicates that most cars have recorded levels below the proposed limit of 1,500 ppm HC before servicing; the average levels dropped below 500 ppm after servicing. What is the point in having a norm that allows almost all vehicles to pass? This `all pass syndrome’ cannot discipline maintenance as is clear from the current diesel fleet on road.

Moreover, CSE’s independent technical study (A Plan for Progress) had pointed out -- based on European experience -- that a new car with a properly functioning three-way catalytic converter should not emit more than 100 ppm HC on road. Europe may have a better maintenance culture and fuel quality to check on-road deterioration. But allowing a higher margin for deterioration for new technologies in India is grossly unjustified. The purpose of vehicle inspection is not to catch only old smoking vehicles, but also to prevent the new ones from deteriorating fast.

Weak test procedures weakens the system further
CSE is appalled that the government has not even redressed the most serious weakness in the PUC system -- the loopholes in the test methods that allows manipulation and evasion. More than the norms, inadequate test procedures compromise the authenticity of tests leaving them wide open to manipulation and evasion. The only procedural change recommended by the ministry to the state governments as an option for petrol vehicles with three-way closed loop catalytic converters is the lambda test – the ratio of air to fuel mixture compared to the theoretically correct ratio. This test will give away any anomaly in the mixture strength due to injector malfunction or tampering.

But no checks are mandated to validate the correctness of tests for carbureted vehicles, both cars and two/three-wheelers that dominate the vehicle fleet in cities. Such checks are possible only with measurement of other parameters such as carbon dioxide and oxygen to detect deliberate dilution of exhaust by entrained air due to improper positioning of the probe in the tailpipe to get the desired concentration of CO and HC.

CSE condemns this ‘one step at a time’ approach, as this will only delay matters with no significant benefit. CSE demands that the PUC test procedures and norms for all types of vehicles be revamped holistically and immediately for the country. The state governments can then focus on developing a future roadmap for phasing in of advanced inspection system in bigger and centralised testing facilities to replace the PUC programme and develop institutional framework for independent auditing and quality control of these centres. Only a credible vehicle inspection programme and rigorously implemented can win public support, cut in-use emissions and even exert pressure on the industry and refineries to improve engine technologies and fuel quality.

Diesel vehicles
Current test: Free acceleration smoke test to measure smoke density
Current Norm: 65 Hartidge unit (HSU)
Draft notification: No change in norms or test procedures indicated

Petrol/CNG/LPG vehicles
Current norms: Measurement of only carbon monoxide concentration in the volume of exhaust at idling

• 2/3 wheelers: 4.5 percent CO by volume
• Cars: 3 percent CO by volume

• Pre 2000 cars: No change
• Post 2000 cars with closed-loop 3-way catalytic converter: 0.5% (by volume)
• Lambda value can be measured

• Pre-2000 two and three-wheelers wheelers: No change
• Post 2000 four-stroke 2/3 wheelers with catalytic converters: 3.5 % by volume.
• Post 2000 two-stroke two and three wheelers with catalytic converters: No change
• Lambda value can be measured

Current norms: Not regulated
Proposed norms
Cars

• Euro-II equivalent compliant cars fitted with 3-way catalytic converter: 750 parts per million (PPM)
• Pre-Euro II cars: 1500 ppm

Two- and three-wheelers:

• 4-stroke fitted with catalytic converter (Manufactured on or after April 2000): 4500 ppm
• 2-stroke (Manufactured on or after April 2000): 6000 ppm
• 2/3-wheelers (Manufactured prior to April 2000): 9000 ppm

Sources:
The Central Motor Vehicles Rules, 1989 (as amended in 2003), Publication – Bare Act with short notes, 2003, Universal law publishing Co Pvt. Ltd