Brussels, Belgium, August 2026 — The Global Covenant of Mayors for Climate & Energy (GCoM), through its Innovate4Cities initiative and together with the Centre for Human Inspired AI at the University of Cambridge and the Urban Transitions Mission (UTM), is calling on innovators worldwide to develop artificial intelligence (AI)-powered solutions to pressing urban climate challenges.

Applications are now open for the third edition of the AI x City Climate Action Hackathon, inviting participants from around the world, including students, researchers, professionals, AI builders, climate innovators, urban planners, data scientists, startups and multidisciplinary teams. Applications can be submitted through the official Hackathon website and will close on 31 August 2026 at 11:59 PM GMT.

The AI x City Climate Action Hackathon is built around a simple principle: start with the challenges cities and local governments face, not the technology. Participants can address any urban climate challenges, with three priority areas this year: transportation, informal or marginalized settlements, and misinformation and disinformation.

These priorities include improving urban transportation through approaches such as predictive routing and electric fleet management; protecting marginalized and informal settlements through better hazard mapping and more equitable service allocation; and tackling climate misinformation and disinformation to strengthen public trust and support informed climate action.

“As accelerating climate impacts increasingly test the resilience of our cities, we need bold and immediate action,” said Andy Deacon, Co-Managing Director of the Global Covenant of Mayors for Climate & Energy. “Through the Urban Transitions Mission - which GCoM co-leads - we are demonstrating practical, integrated pathways that can help cities accelerate decarbonization and resilience. The Hackathon connects cities and innovators to respond to real-world challenges with AI assistance - grounded in rigorous methods, responsibility, and local accountability - to enhance people-centered solutions that are tested and implemented on the ground.”

Previous editions have demonstrated how solutions developed through the Hackathon can progress towards real-world application. DUCTExplorer, from Singapore, won in 2024 and worked with Belo Horizonte, Brazil, to develop city-scale heat maps and analyse heat mitigation options. In 2025, winner Polisense.AI leveraged their $15,000 in seed funding and were matched with cities to explore the real-world application of their solutions, moving their projects towards implementation in Greater Amman (Jordan), Chisinau (Moldova), and Cordoba (Argentina).

“AI has enormous potential to help cities turn complex data into practical, powerful tools for climate action,” said Lu Sun, Director of AI and Tools at C40 Cities. “Through the Hackathon, we get to learn first-hand from innovators how local action can benefit from solutions that leverage AI in ways that are as responsible and technically sound as they are ambitious.”

From Ideate to Hack to Pilot

The 2026 Hackathon follows a three-phase journey — Ideate, Hack and Pilot — designed to help promising ideas progress towards practical application.

Following its launch at the Innovate4Cities Conference 2026 in Nairobi, participants can engage with expert-led webinars and virtual participant hubs designed to help refine their solutions, with access to expert mentorship, technical support and networking opportunities throughout the program.

Up to ten finalists will have the opportunity to pitch their solutions at the University of Cambridge, in England, on the 22nd September 2026, in partnership with the Centre for Human-Inspired Artificial Intelligence (CHIA). The finalists can attend either online or in person. 

The top three teams will be invited to attend the Urban Transitions Mission Global Innovation Summit in Viladecans, Spain, in November 2026. To accelerate real-world impact, UTM will also match select winners with partner cities for local testing and implementation.

Two special prizes will also be awarded in collaboration with Hack for Earth and Tech to the Rescue to offer participants with even more opportunities to scale their solutions.

“At the Centre for Human-Inspired Artificial Intelligence (CHIA), we are committed to advancing AI that responds to real human and societal needs,” said Dr. Ramit Debnath, Executive Director of CHIA at the University of Cambridge. “Climate change is one of the defining challenges facing cities, and this Hackathon gives innovators an opportunity to apply AI to concrete urban problems while learning directly from experts and city practitioners. Our aim is to help participants develop solutions that are not only technically innovative, but practical, people-centered and capable of delivering real-world impact. This hackathon is a unique platform that brings practitioners and academics together to create a feedback loop between knowledge generation and application, which is central to human-centric AI.”