Lecture by Dr. András Gelencsér, Academician, Air Chemist, Rector of the University of Pannonia, at the 1st GreenLike Info Day, organised on the occasion of Earth Day. The GreenLike programme is implemented within the framework of the grant project 2019-1.3.1-KK-2019-00015 "Establishment of a sustainable competence centre based on circular economy at the University of Pannonia".