Cars account for just 2% of Delhi’s emissions
Though Delhi chief minister Arvind Kejriwal is going ahead with his odd-day-odd-car policy to curb the capital’s pollution, both he and the Supreme Court (SC) would do well to study the IIT-Kanpur report submitted to them. On PM10 (particulate matter upto 10 micrometres in size), it says, 56% of the capital’s pollution emanates from road dust, 14% from construction-related activities, 10% from industry and 9% from vehicles. You could argue that it is important to tackle vehicular pollution first since it is easier to handle than, say, road dust—in any case, in the more dangerous PM2.5, vehicles account for 20% of pollution versus 38% for road dust. But 46% of vehicular pollution emanates from trucks, 33% from 2-wheelers that Kejriwal has exempted from his odd policy and 10% from 4-wheelers. So, if odd-even works perfectly, Kejriwal can hope to reduce Delhi’s pollution by just 1% (that’s half of 10% of 20%)—and if you assume there are as many women drivers as men, the impact goes down to 0.5%; and we haven’t even looked at the break-up of diesel versus petrol cars yet. An interesting data point here is that, as the wedding season gets over (think of all those monstrous diesel gensets powering every wedding you have been to in the last month) and as the burning of crop residue ends in Punjab and Haryana, Delhi’s PM2.5 levels start plummeting from January every year—so Kejriwal will get the results he wants since the test is designed to succeed.
The SC’s decision to ban, temporarily, registration of diesel cars/SUVs over 2,000cc, as this newspaper has pointed out earlier, serves little purpose since 70-80% of the capital’s diesel cars are in the sub-1,300cc range—the larger cars, by the way, are not just owned by the rich since the Innovas, for instance, are largely taxis for the not so well-heeled. But, there’s another problem. Emission norms are not set by engine capacity alone, they are set by weight category as well—so a car weighing under 1,305 kg can emit a maximum particulate matter of 25 mg/km, and this rises to 60 for cars that weigh more than 1,760 kg. That’s where the SC ban on heavier cars is coming from, but there are lighter cars that emit as much as heavier ones—in the case of Toyota, for instance, its 4,500cc Land Cruiser emits just 7% more PM than its 3,000cc Fortuner. What matters really is the emission per car, not the size of the engine or the weight of the car. Which brings us to the real issue, of old cars versus new cars that emit much less—PM norms for Category I diesel cars were cut from 80 mg in BS II to 25 mg for BS IV, and will fall to 4.5 mg when BS V norms are introduced. Banning new cars doesn’t help since they emit less, a solution lies in finding ways to phase out old cars which pollute more, while reducing the financial burden on owners – even when BS V fuel is made available, at a huge cost to refineries, this won’t reduce emissions from older cars. Issues like making bus travel easier through special lanes and lowering excise duties on buses remain critical, but there’s little to be achieved by demonising cars.