At present, the country’s carmakers, as they sway in their devotion to diesel, might sympathise with the people the Bible is talking about. It is just that their swaying is not borne out of free will.

Every industry responds to regulation. For instance, our e-commerce companies became market places because of the rules governing foreign investment. Similarly, many carmakers took to diesel because it appeared to be the government’s choice as it kept diesel prices lower than petrol’s.

Still, Maruti Suzuki, the country’s largest carmaker, did not succumb for long.

It dabbled in diesel reluctantly by buying an engine from Peugeot and fitting it into a few Zens and Esteems.

And it waited for the government to let petrol and diesel prices become equal, as it had promised.

And Maruti waited, and waited, and waited. And then it used its partnership with Fiat to obtain a diesel engine and fitted it into the Swift in 2007, its first real diesel car. People liked it so much Maruti set up two factories to make diesel engines. When it still could not meet the demand — now there was the diesel DZire, too — it bought engines from Fiat. In 2012, the gap between the prices of petrol and diesel had climbed to Rs 25. Since diesel cars run 20% to 30% farther than comparable petrol cars for the same amount of fuel, the country of people who always ask “kitnadetihai” lapped up diesel cars. If Maruti had not invested in diesel, it would have lost the burgeoning market.

Several other companies invested in diesel, most notably Honda, not known anywhere in the world for its diesel cars. They do not know what to do now that diesel is acquiring a stigma. It is seen as responsible for filling the air with PM 2.5. This is particulate matter smaller than 2.5 microns, or one-thirtieth the width of a human hair, which allow carcinogens to penetrate deep into tissues and organs.

But engineering and R&D heads at carmakers say that is just one side of the picture. “All fuels — CNG, gasoline, or diesel — come from the same source. They are all carbon-based fuels. Each gives out pollutants with different numbers,” says CV Raman of Maruti.

The irony is that diesel was the favoured fuel when the technology of its engines was still developing, and trucks and buses were bellowing black smoke on the streets. Now that the technology is highly refined, the courts and authorities want to clamp down on diesel cars, even new ones, though trucks, buses, and that freak of a vehicle called Jugaad are still bellowing black smoke, as do cars of a vintage when emission norms were more lax and technology more primitive.

When the Supreme Court drove emission control in the late 1990s, it advised the government to set up centres to certify vehicles. Only one centre in Burari, in Delhi, came up. There is no enforcement of the certification. There is a new policy for scrapping cars, but not much clarity on it. If a large number of vehicles goes to end-of-life, there must be a way to validate that they are indeed ready for their last tide. And you need centres to turn them into scrap. A demo recycling unit was set up in Chennai three years ago; it remains a demo unit.

Then there are commercial vehicles with “All India” permits. They cannot comply with the highest emission norms because the fuel required is not available in many parts of India.

A much-quoted research by the IIT Kanpur shows that cars are responsible for only a small fraction of the PM pollution in Delhi. The biggest polluter is road dust with 38% of the blame. Vehicle emission is 20%, of which trucks account for 46%, and two-wheelers 33%. Yet, the emphasis is on curbing cars, and making their emission match European norms, though much of Europe has no road dust.

The fun may begin when the Bureau of Energy Efficiency comes up with fuel efficiency ratings for cars, which it promises to do soon. The ratings will most likely be calculated on carbon dioxide efficiency. On that, diesel beats petrol hands down.

Will the tide again turn in favour of diesel? But by then diesel cars may be more expensive as they meet higher emission norms, and the higher grade of diesel will be more expensive than it is now. The only thing one can say with certainty is a lot of people will be at the end of their wits.