BS6 vs BS4 vehicles: The pollution gap is bigger than you think

Delhi government has tightened the vehicular movement in the national capital region (NCR) in an attempt to curb the severe air pollution level in the region. Effective from December 18, Thursday, only BS6 vehicles will be allowed to enter the NCR. Under the new norms, all the BS3 and BS4 vehicles registered outside Delhi, will be restricted to enter and ply in the NCR. This move comes as a key part of a series of emergency steps being adopted by the authorities in Delhi-NCR.

In an attempt to curb the air pollution level in the city, the Delhi government has taken several measures, impacting the vehicular movements. The restriction on BS3 and BS4 vehicles comes as a significant one. If you are wondering how the BS4 and BS6 vehicles are different from each other in terms of emitting pollutants, and how these two norms are different in terms of curbing pollutants, here is a comprehensive explainer for your understanding.

How BS6 is different from BS4 emission norms?

BS6 is a more stringent emission standard compared to BS4, primarily differing in reduced sulfur content in fuel. While the BS4 allows sulfur content of 50 ppm, the BS6 allows 10 ppm. This makes the BS6 fuel five times cleaner compared to BS4 fuel, with significantly lower sulfur content. Also, the BS6 emission regulation comes with stricter limits on pollutants like NOx (Nitrogen Oxides) and PM (Particulate Matter).

Also, the BS6 emission standard commands mandatory inclusion of advanced technology like DPF (Diesel Particulate Filter) and SCR (Selective Catalytic Reduction) in BS6 engines. This results in better pollution control, making the BS6 engines more environment friendly, but they require specific BS6 fuel.