If you look at the carbon footprint that India has made ambitious reduction commitments for, these are based on fuel efficiency of vehicles – the Corporate Average Fuel Efficiency (CAFÉ) norms) – where diesel is obviously superior to petrol.
Apart from the obvious hardship that Delhi’s citizens will face with the National Green Tribunal (NGT) ruling that all diesel vehicles older than 10 years have to be de-registered, it is not clear on what basis the NGT reached this conclusion – the same, naturally, applies to the Supreme Court’s ban on registering diesel vehicles of more than 2,000 cc in the National Capital Region or the Delhi chief minister’s on-off odd-even scheme. If it is the particulate matter (PM) that is the issue, as the IIT-Kanpur report brings out, under 9% of PM10 pollution in the capital is caused by vehicles (20% for PM2.5) and of vehicles, four-wheelers account for a tenth of pollution – that, of course, is the reason why there was no discernible reduction in pollution levels during the period in which odd-even was being implemented. If it is NOx, vehicles account for 36% of Delhi’s pollution but, within this, four-wheelers account for 17% of the load and two-wheelers (that do not run on diesel) 27% according to IIT-Kanpur – indeed, few measure the NOx levels of CNG buses/taxis/3-wheelers. If you look at the carbon footprint that India has made ambitious reduction commitments for, these are based on fuel efficiency of vehicles – the Corporate Average Fuel Efficiency (CAFÉ) norms) – where diesel is obviously superior to petrol. It doesn’t help that, as the government affidavit in the Supreme Court shows, certain 3000cc+ diesel vehicles have lower PM emissions than even 1500cc vehicles do.
Before any judgments are made – this applies to even the higher excise duties the government puts on diesel vehicles – there needs to be a proper measurement of the on-road emissions of different types of vehicles. Tests need to be made to see how much of this get fixed by catalytic convertors. After that, the government needs to see how long it will take for refineries and auto-makers to upgrade to higher emission standards – permissible PM levels for diesel and petrol engines are the same under BS VI. Based on this, and the ability to supply cleaner fuels like CNG – the NOx levels of these engines need to be measured – a proper fleet mix has to be drawn up for the country and, if need be, for different states. It is only after this that a proper decision can be taken on whether or not to phase out diesel vehicles – if, as many argue, diesel engines are carcinogenic, they should be phased out anyway and no distinction be made based on whether the engines are 10 years old or less, or whether they are under 2000cc or more. Indeed, if the final fleet mix suggests India needs a lot less diesel vehicles than it is likely to have in a business-as-usual scenario, it has to be ensured that state governments don’t charge lower VAT on diesel — while excise duty on diesel/petrol cars have to be fixed on what this study shows, surely it makes little sense to charge as much excise on buses as is done today since these are a sure-shot way of reducing emissions? Any policy on optimal transportation requires a great deal of deliberation and while it is true we have wasted decades in being ad hoc, it is a pity that such high-impact decisions are being taken with precious little real-time data.