Heavy-duty trucks entering Delhi emit an estimated 52.18 kg of PM2.5 daily [1].

This data highlights a critical gap in urban air quality management, as a small portion of the vehicle fleet generates a disproportionate amount of hazardous pollution. The findings suggest that updating vehicle standards is essential to reducing the city's smog.

According to the report released Monday, BS-III and BS-IV trucks account for approximately 62% of total truck-related PM2.5 emissions [1]. This is significant because these specific categories represent only 38% of the total truck fleet [2].

Breaking down the daily totals, BS-III trucks emit 17.9 kg of PM2.5 [2], while BS-IV trucks contribute 14.47 kg [2]. These older pre-BS-VI models are less efficient and emit higher levels of particulate matter than newer standards, a factor prompting calls for their phased removal from the National Capital Territory.

The scale of the issue is underscored by the volume of traffic. Approximately 16,900 interstate heavy-duty vehicles enter Delhi [3].

There are varying estimates regarding the broader impact of these vehicles on the city's air. One analysis indicated that heavy-duty trucks are responsible for 23% of Delhi’s total transport-related PM2.5 emissions [3]. Other government data suggests a higher combined impact, stating that heavy-duty trucks and buses together account for 35% to 36% of transport-related PM2.5 emissions [4].

“BS-III and BS-IV trucks account for approximately 62% of total truck-related PM2.5 emissions”

The disparity between the number of older trucks and their emission levels indicates that transitioning to BS-VI standards provides a high return on investment for public health. Because a minority of the fleet is responsible for the majority of the particulate matter, targeted scrappage programs for BS-III and BS-IV vehicles could significantly lower Delhi's overall transport emissions more effectively than broad restrictions on all heavy vehicles.