The ground-breaking scheme is set to be the first test of so-called 'clear zones' designed to clean up air in town centres by banning polluting vehicles.
Businesses will be approached by a special team of sales personnel from TransportAction PowerShift for a project called Planet York - a partnership between the Energy Saving Trust and the City of York Council.
Among the incentives to convert to cleaner fuels will be a fast-track response on grant applications with decisions within a week instead of a month.
The project has a target of putting 100 cleaner vehicles on the road and over the course of the year the team will measure any reductions in carbon dioxide emissions, and changes in attitudes and behaviour among drivers.
Daniel Johnson, Travelwise officer at the city council, said: 'We are working very closely with TransportAction on this and with the largest employers in the city, almost all of them will run vehicle fleets. We will be targeting them in the first instance and TransportAction is employing a special team of sales staff for the York area. Businesses will be entitled to a fast-track application process as an incentive.
'We have also given people a choice over what to do about five areas where we have recorded high NOx emission - a problem associated with vehicle pollution.
'Feedback so far has preferred making as wide an area as possible a clear zone, so this is one of the issues we will have to consider, and do not want to rule anything out at this stage.'