The ban on the sale of booze anywhere within 500 meters of a state or national highway has led to a lot of outcry.But there's another "500-metre" order with which the Supreme Court could save lives.In its order on the liquor ban, the court says tens of thousands of people have been killed annually because of drunk driving. It's taken decades of fighting for this ban to be actually implemented, and not because consensus or laws were lacking. In 2004, the National Road Safety Council had unanimously called for these shops to be banned. The 1988 Motor Vehicles Actalso calls for the removal of liquor shops along national highways. But nothing was done.Nothing was done because "influential people" owned these shops, past orders were "surreptitiously violated" and so the Supreme Court, to safeguard against such "subterfuge", decided on the 500-metre ban. But this is not to argue whether the decision was good or bad (though frankly, if it can save lives, the answer may be obvious to many).A greater danger borne out by scientific reports makes the case for a ban on highly polluting vehicles, specifically diesel. Because "people living within 500 meters from any roadside are most exposed to vehicular pollution." This is according to a document given by the court-mandate environment panel chaired by Bhure Lal to the judges.The most polluting vehicle fuel currently is diesel, as per several studies. The Bhure Lal-panel, EPCA, says diesel and coal are more harmful than dust, as they can lead to an increase in ischemic heart disease-related deaths. That's when the arteries get narrowed, and less blood and oxygen reach the heart. For coal, the immediate, biggest source in Delhi is the Badarpur thermal power plant which reportedly accounts for 11% of the particulate matter pollution in the capital which was kept shut for most of last winter.But why ban diesel? Is the science correct? Isn't it too excessive?Consider this:Diesel emissions are carcinogenic, as per the World Health Organisation.Diesel, even with Bharat Stage 4 emission norms, is more polluting than petrol.A landmark IIT-Kanpur report had, in January 2016, recommended the fast implementation of Bharat Stage 6, the latest standard in Europe, for diesel.When Euro 6 is implemented across India three years from today, only then are diesel emissions likely to be at par with those from petrol.But that's only on paper. Already it's been shown that Euro 6 (eventually BS 6) diesel vehicles emit 7x more pollution than they should.This means that even the next gen of 'cleaner' diesel engines that India plans to have soon will fail to meet tighter norms. And this is according to the ICCT , the guys who caught Volkswagen cheating, forcing it to pay billions of dollars as fines and compensation.Practically, of course, there can't be a ban on polluting diesel vehicles for 500 metres on either side of major roads in Delhi or any other northern cities. It will effectively need to be a complete ban.More than half of Delhi's population lives near a major road. Delhi-based CSE reported how a study, between February to May, showed that "short-term peaks during travel can go over 1,000 microgramme per cubic metre - nearly 16 times the daily limit"! And this was in 2011. Since then, more vehicles have been added to Delhi's roads.Statistics apart, it's easy to grasp the problem: Imagine your family's average daily routine, walks on the roads, waiting in a parking lot, driving around...all under a sci-fi type glass dome. The glass dome is effectively the air around us laden, in many north Indian cities at least, with lethal pollutants. Unless it's really windy or raining, or there's very little traffic, the pollutants will linger around and be inhaled by us. The devastating health effects, especially on our kids, is well-documented.But don't expect any government to spur into action against vehicular pollution. Not only has the centre batted for the many of the auto firms opposing the ban on BS 3 vehicles, despite the April 1st deadline being set years ago, but the Delhi government has also not been able to deliver on its promises of improving public transport by adding many more buses. It's a welcome miracle that the government says it will implement cleaner, Euro 6 emission earlier than schedule, but now's the time to track its implementation.Like the booze ban, it's time to stop the subterfuge, the influence of the rich and connected, and to do what's best for all - we all breathe the same air. And the Supreme Court has shown in just a couple of days what it can do if the science and the motive - to save lives here - is right. It banned diesel briefly last year, but can the comprehensive data and global trends convince it to ban it in India's most polluted cities?

(Chetan Bhattacharji is Managing Editor at NDTV)