Abstract:

The cities of Delhi and Gurugram in India’s National Capital Region have faced severe air quality issues for decades, and the road transport sector is a major source of air pollution. The TRUE Initiative, with analysis led by the ICCT and in collaboration with local authorities, conducted a remote sensing testing campaign that provides an independent evaluation of tailpipe emissions from vehicles to support evidence-based policymaking.

The study finds that vehicles certified to the newest emission standard, Bharat Stage (BS) VI, show significant improvements in tailpipe emissions across all pollutants and vehicle types measured. At the same time, real-world emissions from BS VI vehicles in many cases remain higher than type-approval limits. This is particularly the case for high-use commercial vehicles; for example, BS VI taxi and light good vehicle fleets were shown to emit 2.4 and 5.0 times more nitrogen oxides emissions than the counterpart private car fleet. The results also challenge the notion that vehicles fueled by compressed natural gas (CNG) are a “clean” transportation alternative. Across the range of BS VI vehicles measured fueled by CNG, emissions were 1.5–14 times greater than the type-approval limits.