1. How Are BS-6 Norms Different From BS-4?
Bharat Stage VI emission norms drastically reduce the number of pollutants from vehicular exhaust, compared to the current Bharat Stage IV norms. While the difference in emission levels is not that drastic for petrol engines, it is significant for diesel vehicles.
The nitrous oxide emission levels (responsible for acid rain) will drop by 25 percent in the case of petrol vehicles and 68 percent for diesel vehicles. Particulate matter emissions, which is the main concern among diesel vehicles in Delhi, will come down by 89 percent for BS-6 diesel vehicles.
In addition, all vehicles will have real-time monitoring of emissions. All vehicles will have on-board software and OBD (on-board diagnostic) ports to be able to monitor emission levels and give out warnings.
The changes are not related to just vehicles. Fuel quality will also have to be changed, with low-sulphur petrol and diesel being introduced to meet BS-6 norms. Petrol will have to meet a minimum octane rating of 91 RON (which even BS-4 petrol meets).