Why are we measuring this?
Nitrogen oxides are pollutants produced primarily during combustion processes, such as those that occur in older diesel public transport vehicles. A reduction in these emissions contributes to better air quality and public health.
This is aligned with the Government Policy Statement on Land Transport and the Ministry of Transport/Te Manatū Waka’s Outcomes Framework, as well as included in the Regional Public Transport Plan and the Regional Land Transport Plan.
By analysing this data, we can understand the trends in emissions from public transport, assess the effectiveness of policies and initiatives aimed at reducing fleet emissions, and identify areas needing further improvement.
How do we measure the result?
We track kilometres travelled by each engine type and then use an emission model to calculate emissions produced by our public transport services.
What work have we undertaken to contribute to this outcome?
The reduction in NO₂ emissions in 2024/25 indicates a clear improvement in fleet emissions efficiency. The primary contributing factor is the continued transition toward a cleaner fleet composition.
In 2024/25 we welcomed 21 new zero-emission buses to the fleet, bringing the total number of electric vehicles (EVs) to 65, making 26 per cent of our fleet zero-emission. During the year, we reviewed the allocation of zero-emission buses across the Greater Christchurch network to better align vehicle capacity with route demand and maximise the use of EVs in the fleet.
For our MyWay by Metro service in Timaru, a new contract with incumbent operator, Ritchies Transport, will see most of the MyWay fleet become zero-emissions in 2025/26.
Through the Annual Plan 2025/26 process, we delayed funding for EV replacement and infrastructure as part of meeting government expectations around private revenue. This means we will not have funding available over the coming year to add additional EVs to the fleet.
Who else plays a role?
We can implement policies, provide funding, and enhance the sustainability of the public transport fleet to reduce emissions. This includes modernising our fleet, optimising routes, and implementing policies that promote public transport usage over private vehicles.
Partner councils, such as Christchurch City Council, Waimakariri District Council and Selwyn District Council, play a significant role by providing and maintaining the infrastructure required for public transport to reduce reliance on private vehicles.
National transport agencies, the Ministry of Transport/Te Manatū Waka and NZ Transport Agency Waka Kotahi have the ultimate influence over public transport due to their key roles in setting national transport policies and funding for public transport.
Where can I find more information?
Find out more about transport emissions.
Learn about our transition to low-emissions actions in our Climate Action Plan.
