Public health affect everyone hence public health is everyone business. It is as relevant today as it was relevant years ago.

Canadian embassy Japan

According to WHO, health promotion is the process of enabling people to increase control over, and to improve their health. It goes beyond a focus of individual behaviour towards a wide range of social and environmental interventions.

Whatever you do will affect the environment, whether positively or negatively. This in turn will affect your neighbours and vica versa.