A hasty decision, clean diesel is a better bet

The level of air pollution in Delhi during the 90's had reached a magnitude that earned the city the distinction of being labelled as one of the most highly polluted places in the world. Several well known visitors to the capital city including the last Australian cricket team that toured the country shed their politeness to complain about the air they had to breathe in Delhi. The degraded state of air quality in the capital region was the result of collective failure of a number of government agencies at the centre and in the state. And so, the courts had to step in. The problem faced by Delhi is not entirely unique. Several metropolitan areas round the world have faced similar problems of air pollution, but many of them have been able to solve the problem effectively in the past. Better traffic management A large part of the deterioration in air quality comes from the large-scale use of motor vehicles in city centres. Air pollution occurs due to inferior automobile technology, the use of polluting fuels and extensive congestion in vehicular traffic. Congestion is an important factor. Even with relatively clean fuels and advanced engine technology, traffic congestion can lead to high concentration of pollutants in the air at a particular location. It is, therefore, essential that any solution for reducing vehicular pollution focus on all three areas, with improved traffic management providing the quickest benefits. The shift to compressed natural gas (CNG) that came into effect in Delhi on April 1. However, the move does not take into account other steps that need to be considered, nor does the technical advice on which it is based reflect the experience of other cities round the world. Clean diesel route On the basis of extensive trials and measurements carried out with the London bus transport system as well as in New York and in Western Australia, the authorities in these locations have taken a decision to favour Ultra Low Sulphur Diesel (ULSD) fuel over CNG. In the UK, for instance, the city fleets throughout the country would now move to the use of ULSD, which contains .005% sulphur. This choice was based on extensive trials in which pollution levels with ULSD and CNG were measured and the performance of several vehicles evaluated under normal city traffic conditions. It has generally been found that a ULSD burning diesel vehicle fitted with a particulate trap emits a lower level of emissions as compared to a CNG bus for all pollutants except oxides of nitrogen. One set of emissions, namely carbonyls, which are labelled as "hazardous air pollutants" by the United States Environmental Protection Agency, is almost entirely eliminated with ULSD. The Supreme Court had set up a Committee to render advice on actions that need to be taken for reducing air pollution in Delhi. This Committee did not seriously consider any option other than the elimination of diesel buses and a large-scale switchover to CNG. Nor does it appear to have considered the costs and practical problems in such a massive shift involving 10,000 buses from the use of diesel to CNG. As it happens, there is no city in the world that has even one-tenth of the number of 10,000 buses targeted in Delhi, using CNG. California, which has some of the strictest air quality standards in the world, has also not considered it desirable to abandon the clean diesel or ULSD route. Los Angeles, which has a fleet of 2600 buses, has less than 1000 running on CNG. In most other cities throughout the world typically several buses are converted to CNG as well as ULSD and their performance then evaluated in environmental, economic and technical terms. A decision on the large-scale use of one fuel or the other is then made on the basis of results from such trials. No such approach was adopted in Delhi, and the committee responsible for coming up with viable and effective options went down the CNG road with consequences that are now being faced by the residents of Delhi. There can never be any dispute on the rationale for protecting the health of the millions who would suffer the ill-effects of alarming levels of air pollution in Delhi. Yet it is quite reasonable to expect that the decision makers would diligently explore all options along with their implications, before settling on one or the other. The question, arises, where do we go from here? The conversion of petrol vehicles such as taxis and three wheelers to the use of CNG is a totally desirable action and must be pursued. As for the city's bus fleet, it is necessary to allow a large number to convert to ULSD. Since Indian refineries are not currently producing this fuel, it should be possible to import the small quantity that would be required for about five to six thousand buses that could be converted. Regular checking of fuel quality can dispel the fear of adulteration of this fuel. Besides, with the dismantling of the Administered Price Mechanism for petroleum products announced for the end of this fiscal year, the differential between kerosene, used for adulteration of other products, and diesel would narrow substantially. If the authorities in Delhi don?t wake up to these challenges, then the move to CNG may remain the nightmare that it seems now.