The aim of the project proposal is to improve ambient air quality in the Municipality of Vratsa by reducing the levels of fine particulate matter and nitrogen oxides as a result of the replacement and modernisation of the rolling stock of the public transport media. The implementation of the project will contribute to meeting the needs of the population, tourists and guests, companies and organisations in the municipality of Vratsa, for clean air, modern and environmentally friendly urban transport. The supply of 13 new electric buses and 9 new trolleybuses, complying with European engine emissions standards and the use of renewable energy sources in urban transport, is planned. Provision is made for specialised equipment to optimise the operation of trolleybuses and installation of charging stations for electric buses. The project includes activities for the supply of electric vehicles; specialised services; optimisation of the operation of newly acquired vehicles, including implementation of an integrated transport management system (for electronic charging and real-time passenger information), collision avoidance systems, refurbishment of the catenary network, construction of cable routes to charging stations and delivery and installation of TEC cartridges (correction station), initial registration and insurance, publicity measures. The activities were developed after a cost-benefit analysis, which demonstrated the relevance of the project and the sustainability of the results. The expected results are the reduction of PM levels, noise and vibration levels and energy savings, the reduction of the use of non-renewable energy sources such as diesel fuel and its replacement with electricity, the development of sustainable urban transport, the reduction of the use of private cars, an increase in the share of public transport users, which, through the realisation of the project, becomes attractive, convenient and secure.