Towards a climate neutral EU:
efficient allocation of EU funds

INNOAIR - Innovative demand responsive green public transportation for cleaner air in urban environment

Organisation: EPI Website: Added: July 29, 2022
Project start date: July 01, 2020
Project end date: June 30, 2023


The INNOAIR project addresses urban air quality and transport inefficiency in Sofia, Bulgaria’s capital and largest metropolitan area. The project is designed to “test new and unproven solutions to address urban challenges” that are scalable and transferable to other urban hubs across the country and throughout Europe.

In Sofia, pollution and poor air quality are long-standing and complex problems that derive from natural and geographic specificities, but worsening conditions in recent years have demonstrated the detrimental effects of human activity. The city's population has grown by 10% in the past decade, and new residential and office districts have sprung up as well. The number of vehicles registered in Sofia grows each day, with an estimated 70 cars per 100 inhabitants (the EU average for other major cities in Europe is 45 cars per 100 inhabitants). At the same time, Bulgarians drive some of the oldest cars in the EU: in 2017, 25% of all vehicles were more than 20 years old, and a further 60% were between 10 and 20 years old. Traffic has the greatest detrimental impact in terms of pollution of ambient air in Sofia.

The innovative solution introduced through the INNOAIR project is ‘on-demand green public transportation’, which can lead to air-quality improvement, improved traffic flow, and behavioural change. The project delivers a set of tools that will help reduce single vehicle journeys and improve air quality in the city.

Upon completion of the INNOAIR project, Sofia will have a pool of coordinated policy tools, including:

• ’on-demand green public transport’ comprising a platform with machine learning and advanced analytic capabilities and mini electric buses;

• a congestion charge model;

• low-emission geospatial urban zones that prevent vehicles from entering the city centre and certain areas on ‘high pollution’ days; and

• green corridors for active transport.

‘On-demand green public transport’ will change how the public transport network operates. Instead of driving along pre-defined routes, the new electric, emissions-free buses will create a route map based on citizen demand submitted via mobile application. The app will leverage AI, machine learning and advanced data analytics to create the most efficient path for each ride, while collecting as many passengers as possible.

This innovative service is being implemented as a pilot in a fast-developing suburban residential district of a city that currently lacks convenient and reliable public transport connections to the city centre.  At present, 48% of citizens in the Manastirski livadi district use their personal vehicles each day, with 37% stating that they do not have a transportation alternative. The idea of ‘on-demand green public transport’ is to provide suburban residents with efficient and sustainable mobility options to reach any metro station that connects to the city centre.

Timeline: A digital tool with incentives for switching to public transport or active transport was released in October 2021. Low-emission geospatial zones were mapped and tested in December 2021. Green corridors for active transport will be mapped in October 2022. The congestion charge model will be developed in February 2023. A series of 12 ‘Beat Air Pollution’ citizen challenges will be introduced in May 2023. Finally, on-demand green transportation will be established in June 2023.

INNOAIR good practices and innovations: The project consortium is a good example of a public-private partnership (PPP) that involves a variety of stakeholders, thus making the project a gateway for more inclusive green transition policy at local level. The project features a comprehensive and tailor-made communication campaign intended to further stimulate citizen participation through reward systems, mobile apps, public events (e.g., hackathons), and science and research activities. The project successfully combines green transition efforts with digital transformation, thus laying the groundwork for ‘smart city’ development.

Financial data

Total budget granted under the European Regional Development Fund via the Urban Innovative Actions initiative of the EU: € 3,712,553.52 


Despite its innovative nature and intended purpose as a testing ground for scalable, transferrable solutions, the project fails to provide clear emissions reduction targets. The fact that the project relies heavily on citizen participation makes it difficult to predict the level of impact that project acitivities will have on air quality improvement and transport efficiency. The project faces some administrative and regulatory challenges related to consent on the collection, processing and use of the bid data generated from mobile app activity. However, a successful resolution could create a meaningful precedent and pave the way for streamlining such regulations, thus supporting project transferability and scalability. Another legislative issue relates to the idea to charge a penalty fee for road congestion, which would require changes to municipal-level regulations and subsequent approval by the Municipal Council. The controversial nature of a congestion charge could lead to a prolonged political discourse and delay project implementation. The measure’s rationale and expected positive impact on air quality have not been clearly communicated through an otherwise comprehensive public relations campaign.

Information sources

Other info

European Climate Initiative (EUKI)
This project is part of the European Climate Initiative (EUKI). EUKI is a project financing instrument by the German Federal Ministry for Economic Affairs and Climate Action (BMWK). The EUKI competition for project ideas is implemented by the Deutsche Gesellschaft für Internationale Zusammenarbeit (GIZ) GmbH. It is the overarching goal of the EUKI to foster climate cooperation within the European Union (EU) in order to mitigate greenhouse gas emissions.