Demand for energy is continually growing, and the quality of air, that has a significant impact on the health of the population, is related to it. Slovakia has long-term problems with air quality, with the main cause of the current situation being emissions from household heating and transportation emissions. Negative impacts mainly affect places with highest population concentration. A priority issue in the concept of smart cities should be energy efficiency with a long-term ambition of zero emissions and energy self-sufficiency, which is closely linked to the construction of "green infrastructure", the implementation of measures to mitigate climate changes, the zero-waste circular economy, electromobility and reduction of external noise. The first step should be the analysis of all available data, assessment of their interrelations as well as predictions of future developments, which will provide the basis for creating an action plan containing measures for achieving the long-term goals in building of Smart Cities.