Is compressed natural gas (CNG) a clean, non-polluting auto fuel, which does not pose health hazards? This is an issue that has eluded a clear-cut answer, though CNG is being aggressively promoted as a preferred fuel for vehicles. This controversy has been triggered afresh following claims by the Council of Scientific and Industrial Research (CSIR) that CNG-run vehicles emit dangerous nano-carbon particles. CSIR director-general M O Garg said the presence of nano-carbon in the exhaust from a CNG-operated bus has been confirmed by a real-life case study in Delhi conducted jointly by the CSIR, the Dehradun-based Indian Institute of Petroleum and the University of Alberta (Canada). He claimed that tiny carbon particles, containing carcinogenic polynuclear aromatics, can pass through the lungs to the bloodstream to cause cancer. Some doctors claim, however, such ultra fine particles are most likely to get exhaled instead of staying in the respiratory system. And the Centre for Science and the Environment, on its part, has maintained that the emission levels of nano-particles and other pollutants discharged by newer CNG buses are close to Bharat-VI (equivalent to Euro-VI) emission standards. Buses run on ordinary diesel without particulate traps, on the other hand, emit 600 to 2,000 times more pollutants. This is notably not a statement on the merits of CNG vs diesel, but on the virtue of regulating all fuels; after all, diesel and petrol too can reach "close" to, and beyond, Euro-VI levels.
A science-based and peer-reviewed non-controversial verdict on this issue is vital to guide the public policies on vehicular fuel. Rather than mandating one fuel or the other, the imperative is to induce a switch among auto-makers and fuel producers to less-polluting versions. The least that can be done is to expedite the implementation of the Saumitra Chaudhuri committee report, submitted last year, which outlines an auto fuel emissions roadmap till 2025. It has recommended that the Bharat-V (or Euro-V) standard should be introduced all over the country by 2020 and that India's refineries should stop producing Bharat-III fuel and move to Bharat-IV fuel by January 2017. At present, the use of Bharat-IV is confined to only 30 cities. The committee wanted all of north India to switch over to Bharat-IV by April 2015. Environmental activists, though, want this change to be hastened so that the country can leapfrog straightaway to Bharat-VI fuels by 2020. Certainly, implementing the report would end the current odd patchwork in which some fuels are legal in Delhi, but others are legal just outside it. This contradiction does not help clear the air at all.
Oil refineries would need to make heavy investments, estimated by the Saumitra Chaudhuri committee at over Rs 80,000 crore, to produce fuels conforming to Bharat-V standards. It would, obviously, be still higher for fuels compliant with Bharat-VI. The auto makers, too, would need to invest in changing the engine designs to suit higher-quality fuel. There will thus be much lobbying against these standards. The government should stand firm. Higher standards are crucial to safeguard environment and human health.
