BS-VI fuel: A breather for the fight against Delhi's air pollution

Delhi’s battle against air pollution turns worse every year. Amid the blame game, vehicular pollution has always been a concern. 

The city has dabbled with CNG-based public transport fleet, the infamous odd-even plan and several other draft plans that were not much of a success. During the winter in 2017, PM2.5 levels touched a hazardous mark of 500 micrograms per cubic meter.

The decision to roll out BS (Bharat Stage)-VI fuel in the national capital from April 2018, therefore, comes as a relief. With this, India would be much ahead of other countries in adopting the clean fuel at a large scale. 

Vehicle compatibility and ground-level impact, however, remain contested.

BS-VI fuel has 10 ppm (parts per million) of sulphur as against 50 ppm in BS-IV. Further, the BS-VI standards mandate PM emissions are reduced to 0.005 g/km from the BS-IV standard of 0.025 g/km.

With BS-VI fuel, a car for every one km will emit 80 per cent less particulate matter and nearly 70 per cent less nitrogen oxide, explained Hem Dholakia , a senior research associate with Council on Energy, Environment and Water (CEEW). “When these benefits are summed over the number of vehicles in Delhi, the pollution reduction is substantial,” he said.

Dholakia stressed for strict monitoring of vehicles for a successful shift towards BS-VI. “The shift to clean fuel is a welcome step in reducing vehicular pollution. 

We need to strengthen the monitoring framework to check that vehicles are compliant with the new standards. This can be achieved through on-board diagnostic testing  (currently not performed in India) as well as developing new testing cycles that mimic on-road emissions,” he said.

While the government has made it mandatory to adopt BS-VI in Delhi, experts want awareness programmes to support the move. Many consumers would have to be informed about the benefits of the new fuel.

“Vehicles that have emission control systems will perform even better with BS-VI. Whereas for the old ones, it opens up the option of retrofitting. A new clean fuel reduces wear and tear and improves vehicle’s performance,” Anumita Roychowdhury, executive director, Research and Advocacy, Centre for Science and Environment (CSE).

According to data available with CEEW, there were around 10 million registered vehicles in Delhi in 2017. Of these, one-third (nearly 31 lakh) vehicles were cars and the rest were two-wheelers. However, not all of these vehicles may be plying as there is no system of de-registration once an automobile is scrapped. 

Studies estimate that in Delhi, vehicles together contribute between 15 per cent-25 per cent to PM2.5 levels.

As not many vehicles have compatible engines, a ground-breaking impact would take time. “We may see the benefits once a sizable number of vehicles have transitioned to BS-VI. This will take a couple of years as there is a lag between policy implementation and impact,” said Dholakia, “Studies show that there would be pollution reduction benefits by using BS-VI fuel in cars which have BS-IV engines. The benefit will be around 40per cent-50per cent reduction in pollution for every kilometre travelled.”

So far, only Mercedes-Benz and BMW have introduced BS-VI compliant vehicles in India. “Given the policy announcement, I believe other car manufacturers will transition to providing BS-VI vehicles in the near future,” he said.

Citing global experience, Roychowdhury said with the current , 8-9 per cent reduction in PM2 and toxic sulphur levels is possible. By 2020, new vehicles would need to have BS-VI complaint engines and this would help achieve the target.

So, will Delhi breathe easy in the coming winter? “Slightly,” opined Roychowdhury. “Graded Response Action Plan (GRAP) should take care of the rest. There are several other variables impacting air pollution levels and they would also need significant attention,” she said.

The GRAP was prepared by the Central Pollution Control Board last year on directions of the Supreme Court. It enlists several contingencies and long-term measures to be taken to reduce air pollution and toxic components in the environment through a step-wise plan.

“Further, we need to complement this through measures that address mobility needs of people. Some measures are a transition to zero-emission electric vehicles, investing in better public transport (on the supply side) as well as congestion fees and zoning (demand-side interventions),” said Dholakia.