According to the World Health Organization Fumes from diesel engines can cause cancer and could be just as dangerous as asbestos. The International Agency for Research on Cancer is a part of the World Health Organization, had in 1989 labeled diesel exhausts as probably carcinogenic to humans. They have now stated it as a definitive cause of cancer. Reclassifying diesel exhaust as carcinogenic puts it into the same category as other known hazards such as asbestos, alcohol and ultraviolet radiation. For a large country like India where a majority of the commercial transport vehicles run on diesel the effect can be far greater than anticipated as pollution norms in the country are often ignored and regulation is not as strict. While Delhi can claim credit for replacing its entire public bus transport with compressed natural gas kits that are fitted in these buses, truck owners have not complied with changing to using this cleaner fuel citing high cost for the units. Diesel constitutes about 44% of total consumption of petroleum products in the country. The railways too use a number of diesel engines to ferry passengers and goods to different parts of the country as using electric engines is many states is unreliable due to shortages and power cuts. Many cities in India have seen a steep rise in the number of diesel vehicles in recent years. As the gap between the prices of diesel and petrol widens, the sale of diesel variants are now preferred while petrol car inventories have piled up. Euro IV emission standards are in place in only 13 cities in India; the rest of the country still follows Euro III standards. Experts say automobile manufacturers will now have to work on ways to manage exposures to diesel exhaust or design vehicles that run on cleaner fuels so that the effects from fumes are significantly reduced.