Environmental Impact Assessment (EIA) is a systematic process used to identify, predict, evaluate, and mitigate the environmental and health impacts of proposed development projects before decisions are made. In the context of environmental health, the basic principles of EIA are centered on safeguarding human health, maintaining ecological balance, and promoting sustainable development by integrating environmental considerations into planning and decision-making processes. One of the fundamental principles of EIA is the precautionary principle. This principle emphasizes that when an activity raises threats of harm to the environment or human health, precautionary measures should be taken even if some cause-and-effect relationships are not fully established scientifically. In environmental health, this means that potential exposure to pollutants, toxic substances, radiation, or biological hazards should be carefully evaluated and controlled before a project is approved. For example, in the construction of an industrial plant, even if the exact long-term health impacts of certain emissions are uncertain, preventive controls such as emission treatment systems and buffer zones should be incorporated. Another key principle is the principle of prevention. EIA aims to prevent environmental degradation and associated health risks rather than merely reacting to them after they occur. Preventive action is more effective and economical than remediation. By assessing air quality, water contamination risks, noise levels, and waste generation in advance, EIA helps design projects in a way that avoids adverse impacts on communities. For instance, in urban infrastructure development, proper site selection and design can prevent issues such as water stagnation, vector breeding, and respiratory illnesses due to dust and emissions. The principle of sustainability is also central to EIA. Sustainable development requires that present needs be met without compromising the ability of future generations to meet their own needs. In environmental health terms, this means ensuring that projects do not degrade natural resources such as clean air, safe drinking water, fertile soil, and biodiversity, all of which are essential determinants of public health. EIA evaluates long-term impacts, including cumulative effects, to ensure that development does not lead to chronic health problems, ecological imbalance, or resource depletion. Public participation is another essential principle of EIA. The involvement of affected communities, stakeholders, and experts ensures transparency and inclusiveness in decision-making. Local populations often possess valuable knowledge about environmental conditions and health issues in their area. Through public hearings and consultations, concerns about pollution, displacement, occupational hazards, and