Weed them out

The challenge is how to isolate "gross polluters" from the vehicle fleet and send them back to the manufacturers

Last Updated: Sunday 28 June 2015

Weed them out

There is significant evidence suggesting that not the entire fleet but only a small fraction of badly-maintained vehicles with technical flaws contribute disproportionately to air pollution. The challenge is how to isolate them from the rest of the vehicles and weed them out. Due to the sheer volume of periodic checks required and the added problem of public nuisance, city authorities in several other countries are focussing more on the smaller number of most polluting vehicles for more effective results. The Financial Times Automotive Environment Analyst reports that a survey by oil giant Shell indicates that 20 per cent of vehicles emit more than the remaining 80 per cent combined. It has also been estimated that 50 per cent of noxious pollutants is caused by only 10 per cent of motor vehicles.

Furthermore, the most unexpected findings from the 1989-1991 roadside surveys undertaken in California are:

on an average, idle emissions increase as vehicles age because older vehicles have more lenient norms and they emit more due to deterioration;

About 40 per cent of the oldest vehicles have low emissions. In other words, not all old vehicles have high emissions;

High emitters are found in all model years, not just in oldest vehicles; and

60 per cent of low idle co and hc emissions each were emitted by 10 per cent of the fleet. This essentially means that a small percentage of vehicles are responsible for disproportionately large emissions and high emitters can be spotted across all model years.

While the proportion of gross polluters in the vehicle fleet is likely to be small in industrialised countries where the overall technology of the fleet is more advanced, the proportion will be larger in developing countries with polluting technology. A World Bank study states that the average polluting vehicles are higher in developing countries than industrialised countries. If weeding out of 10 per cent of vehicles in the industrialised countries can reduce emissions by 60-70 per cent, more would have to be dumped in India for similar results. This will mean more problem for the consumer and harassment unless the industry is forced to move towards better standards fast.

A similar pattern has been observed in other countries as well. The highest emitting 20 per cent cars in Bangkok, Thailand, accounted for about 50 per cent of measured co emissions. Likewise, 20 per cent of the buses accounted for 50 per cent of the measured smoke emissions.

Even in India, limited surveys show that vehicles that need major repair for controlling pollution are very small. The Indian auto industry's own attempt at checking pollution lends credence to this concept. Emission testing camps organised by Bajaj Auto Ltd ( bal ) during 1996-1997 have shown that the proportion of vehicles that need to be put off the road is as low as 6 per cent. The majority of vehicles on road meet emission norms. According to N V Iyer, bal 's general manager, of the 60,000 vehicles checked in their camps, about two-thirds met emission norms. "A fairly large percentage of the vehicles that did not meet norms could be rectified with minor engine tuning. Only 6 per cent had to be dealt with in garages," he says.

But officials and scientists in India do not read their own data. In a World Bank-sponsored workshop in April, 1998, Automotive Research Association of India ( arai ), Pune, had presented emission data of in-use vehicles to prove how i&m programme can help to reduce emissions in India. As expected, the industry-supported organisation argued that i&m programmes work.

arai is the most unabashed pro-industry organisation in the country and yet the government of India has given it the responsibility to certify the emissions of the new vehicles. Interestingly, a more detailed scrutiny of the same data by the Centre for Science and Environment (cse ), a New Delhi-based non governmental organisation, showed that there is no direct correlation between age and emissions and that even new vehicles pollute more than old vehicles. Thus, even the arai data proves the concept of gross polluters (see box: Small is dangerous ). When cse sent its analysis to arai , there was not even an acknowledgement from this "prestigious" organisation overseen by the ministry of surface transport and the ministry of industry.

There are good reasons to feel sceptical about the effectiveness of i&m schemes, especially the high cost it entails and widespread inconvenience it causes only to isolate a few big polluters. The countries that are now wiser are, in addition to removing gross polluters from the fleet and disciplining consumer behaviour, netting in the manufacturers as well to make them accountable for the emission performance of the vehicles they produce. Using remote sensors and on-board diagonistics, they are already able to identify gross polluters (see box: Catch the culprit).

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