The scientific evidence for human induced climate change and environmental degradation is unequivocal. Accelerating the development of Climate Change Mitigation Technologies (CCMTs) is a key challenge to temper the costs associated with climate change and air pollution. In this project, we investigate the impact of environmental policies on innovation activities in general, and CCMTs in particular. Our methodology makes use of original data at the regional level on environmental measures implemented to decrease air pollution in the European Union and data on patents relating to CCMT (and non-CCMT). Using a quasi diff-in-diff setting, we are able to identify consistently the influence of a stricter environmental policy on different patterns of innovation activity.