This research paper introduces ENIGMA, an innovative platform designed to support decision-making and monitor CO2 levels within Thessaloniki's urban environment. ENIGMA serves as a versatile tool that integrates data from various urban elements, such as infrastructure, buildings, traffic and green spaces, utilizing advanced algorithms to extract valuable insights into CO2 emissions. The primary focus of the paper delves into ENIGMA's pivotal role in the transportation sector, exploring methodologies of transitioning to electric public transport and vehicles. The electrification initiative discussed involves calculating the cost of replacing conventional fleets with electric vehicles and quantifying the resultant reduction in carbon dioxide emissions. ENIGMA's user-friendly interface enables stakeholders to simulate and assess scenarios, such as replacing municipal fleets and transitioning the urban bus fleet in Thessaloniki to electric buses. The presented findings underscore ENIGMA's integral value in environmental planning, particularly in enhancing the sustainability of urban transportation systems. This investigation emphasizes the platform's potential contribution to urban environmental strategies, positioning ENIGMA as a vital tool for promoting ecological resilience and sustainable urbanization. Additionally, ENIGMA's capabilities can contribute to achieving climate neutrality by effectively managing CO2 emissions and promoting renewable energy sources.