Bradford Council is offering grant funding of £1.6 million to bus companies to help make their vehicles cleaner and produce less pollution.
The new funding is being made available to help businesses meet Clean Air Zone (CAZ) standards ahead of its planned launch in the area in January 2022.
There are thought to be around 100 buses that currently do not comply with the Clean Air Zone standards - which mean they emit higher levels of nitrogen than those with a Euro 6 diesel engine or ones that run on alternative fuels.
Grants of up to £16,000 will help operators to replace or retrofit their buses with equipment to reduce the pollution they emit.
Funding is available for both scheduled and tendered services.
The council said it will be announcing further funding applications for taxis, vans, minibuses, HGVs and coaches and business owners can submit an expression of interest form.
The Bradford CAZ, which will not be charging privately owned passenger cars, will cover the area inside, and including, the Bradford outer ring road.
It will also extend out along the Aire valley corridor, (Manningham Lane/Bradford Road and Canal Road area) to include Shipley and Saltaire.