The Supreme Court’s ban on the registration of new diesel vehicles just on Wednesday morning has already set off a massive debate on two fronts: just how bad diesel is, and why should vehicles take the blame for the impact of diesel on Delhi’s air quality?
First the facts. Delhi had guzzled 11.32 lakh tonnes of diesel in 2013-14 alone, 39.6 per cent more than the 8.11 lakh tonnes it consumed just four years ago. Policy experts and scientists, including the SC appointed EPCA have repeatedly pointed out that the spike in the use of diesel from 2007-08 actually mitigated the gains made in Delhi’s air quality when it converted public transport to CNG. In the late 1990s, diesel-fuelled vehicles constituted only four per cent of the total car sales in Delhi, the EPCA recorded in a 2007 report, adding that the number had reached 24 per cent in 2006. Today, diesel cars account for almost half of total sales in Delhi and NCR.
The reason for this was the sharply diminishing gap between the cost of CNG and diesel. In June 2010, the cost of a litre of diesel was Rs 40.10, and CNG Rs 27.50 per kg. Today, diesel costs Rs 48.26 a litre and CNG Rs 37.55 per kg. The EPCA told the SC in a report last year, “In 2002-03, CNG was cheaper than diesel by about 46.71 per cent. Between 2004 and 2009 the difference widened further to more than 50 per cent as diesel prices increased… In December 2013, the price differential (had) plummeted to 7.35 per cent,” the report said. “High CNG costs hurt public transport and undermine (the) clean fuel program,” it added.
As reported by The Indian Express in the `Death By Breath’ series, in 2007, former Delhi chief minister Sheila Dikshit wrote to the Centre, seeking approval for proposed ban on the registration of diesel cars in the capital and requested separate emission norms for vehicles in the National Capital Region (NCR), including the satellite cities of Noida, Gurgaon and Ghaziabad. Here she said the increase in diesel cars was depleting the gains of CNG. In March 2008, the request was turned down, the government couldn’t impose a ban on vehicles plying on a certain type of fuel was the argument. That was the same year when particulate matter 10, the bigger particles in Delhi witnessed a sharp spike from 161 µg/m3 in 2007, drying up the gains of the CNG move.
That said, the spike in diesel car sales has been accompanied by the mushrooming of mobile towers and malls, all of which use generator set, which run on diesel. A 2013 pollution inventory prepared by Dr Sarath Guttikunda found that diesel combustion from generators contributed 6 per cent of PM2.5 and 10 per cent of PM10 levels in Delhi and satellite towns. “Though the overall percentage is small, when spatially segregated these emissions are substantial,” says the study.
So why then has the onus of pollution from diesel fallen only on cars? According to a January 2014 report from the ministry of petroleum and natural gas on the distribution of the sources of diesel, at 28 percent, goods vehicles accounted for the highest. Second to this were private vehicles, which according to the government, contributed to 13 percent. Use of diesel in agriculture was also 13 percent, followed by buses at 10 percent. Industry and commercial diesel vehicles were each contributing nine percent in the diesel use.
Mobile towers at two percent were contributing the least to diesel use, according to this government report. Scientists, however, say this number appears to be grossly underestimated. A telecom-specific emission inventory was published in 2011 by Dr Saroj Kumar Sahu, a post-doctoral fellow at Forschungszentrum Julich, Germany, and Dr Gufran Beig, project director of SAFAR under the Ministry of Earth Sciences. It puts the emission from the sector nationwide at three times all emissions in Delhi, where 14,326 towers generated 2,123 tonnes PM10 per year. Dr Beig said, “We found that after vehicles, the telecommunication sector was the second most common user of diesel.’’ In Delhi, the problem was compounded particularly in NCR, where power supply is erratic.
WHAT DOES DIESEL DO:
A 2013 study by the International Council on Clean Transportation, titled “Impact of standards on premature mortality and emissions: India in global context”, found approximately 10 per cent of all years of life lost from exposure to vehicle emissions around the world occur in India.
Though there are no India-specific studies yet to show the association between diesel fumes and cancer, the international alarm bells have been blaring. In 2012, WHO moved diesel up from its position for 25 years in the risk category of “probable carcinogen” (Group 2A) to “known carcinogen” (Group 1) for lung cancers. The France-based International Agency for Research on Cancer under WHO based this decision on two epidemiological studies published by the National Cancer Institute in the US. Dr Christopher Portier, chairman of the IARC working group, said in a statement in June 2012, “The scientific evidence was compelling and the working group’s conclusion was unanimous: diesel engine exhaust causes lung cancer in humans.”
A recent study fromt Zuyd University in the Netherlands has shown that inhalation of diesel fumes causes stress responses in the brain, which in turn causes cellular damage in the long term. Such oxidative stress in the long term has been associated with diseases such as Alzheimer’s and Parkinson’s. Several studies have also indicated adverse effects on foetal development when pregnant women are exposed to diesel fumes. Scientists from the Danish National Research Centre for the Working Environment have shown in trials with mice that inhalation of the fumes can damage foetal DNA.
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