The European Commission has launched a call for expression of interest for cities willing to join the European Mission ‘100 Climate-Neutral and Smart Cities by 2030', one of the five missions identified in the Horizon Europe Strategic Plan. The objectives of this mission are to achieve 100 climate-neutral and smart European cities by 2030 and to ensure that these cities act as experimentation and innovation hubs to enable all European cities to follow suit by 2050. In the call launched on 25 November 2021, European cities with the ambition to move ahead in their green transition, are invited to submit information about their current circumstances and work, as well as their future plans to reduce greenhouse gas emissions. Joining the mission will put the selected cities right at the innovation forefront of the transition towards climate neutrality, as part of the European Green Deal. Cities can respond to the call until 31 January 2022.