The beginning of this century watch established and developed of Mega cities at many Arabic countries, most of them in the desert areas and with different ideas and trends that using the concepts of sustainability and smart green cities. In view of the enormity of these cities, their large areas and population size and the fact that they contain multiple activities as trade, administration, and various services at all levels, the environmental impact of these cities will be severe and proportional to their size, function, and population size, especially with the outbreak of epidemics (Covid 19) in addition to the succession of natural disasters and the negative impacts of climate change. This is in addition to the fact that social interaction will be different due to the large number of people moving onto these cities and the multiplicity of their social characteristics acquired from their previous place of living in different regions and environments. Therefore, dealing with this kind of cities and its planning methodology is a more complicated and unclear process.
There are many ways and methods of how to predict environmental impact and measuring methods of social interactions, especially in an era in which plagues and all kinds of disasters that threaten health and life in all societies, therefore this requires modern compatible foundations and standards that needed to be included in the planning of Mega cities in the Arab world. The current study aimed to establish a methodology on the environment and population social interaction for new megacities and its surroundings, then establish suitable planning methodology that contributes to development of another megacities, and to reduce the negative  environmental impacts and enhancing the quality of life that increase the positive interaction of the citizens in these cities with the inclusion of the process of continuous evaluation of the stages of planning and implementation and its steps, and then taking the appropriate decision toward off risks to reduce the negatives and maximize the positives impacts. The descriptive analytical approach and the comparative analytical method were used in the chosen case study. The study indicated that there was coastal erosion in some areas adjacent to the new megacities as El Alamein, New Mansoura and Port Said East. These cities will still suffer in the future from the increase of unplanned population activities.