An analysis of the situation in one of the regions of the Russian Federation was carried out on the basis of the official information available. Mortality in the region has been declining for several years until 2020. However, the trend continued in the largest city of the region. Comparison of the estimated pollutant emission masses in Rostov-on-Don with the maximum permissible load on the ecosystem shows their exceedance by the main pollutants by a tenfold, which indicates the importance of the environmental factor for public health. It was noted that under restrictions associated with the outbreak of infectious diseases, the environmental factor for the territory had declined and other factors were likely to increase. Different approaches can offer a range of tools, which implies the need for scientific discussion based on current developments. Refusal to explore alternatives creates moral risks for the informed party. The experience of 2020 allowed accumulating competencies and working out actions for the formation and implementation of a strategy of behaviour in the future. One of the dominant factors contributing to the improvement of public health is the preservation and strengthening of immunity. Common effective means of increasing immunity in urban environments are considered.