Trends in Metlink bus fleet emissions of CO₂e and harmful pollutants are presented up to 30 June 2025. Fleet electrification has delivered substantial emissions reductions, although progress has stalled and partially reversed in since2023/24. The trend reversal is due to growth in diesel bus mileage (as well as electric) needed to meet rising service demand. Air quality monitoring on Wellington’s Golden Mile shows that while air pollution levels remain well below 2018/19 levels, the improving trend has reversed since 2023/24 consistent with higher diesel bus activity.

Mitchell T. 2025. Metlink bus fleet emissions 2024/25: Environmental performance report. Greater Wellington Regional Council, Publication No. GW/KI-T-25-26 Wellington.