Environmental impact assessment refers to the investigation, prediction and evaluation of what impact the plan or project will have on the atmosphere, water, soil, organisms and the environmental system composed of them, and what impact the results of these impacts will have on human health and living environment, as well as the natural environment, economy, culture and historical environment, Based on this, the countermeasures and measures to prevent or reduce environmental pollution and damage are formulated.
The behavior of organizing relevant departments to evaluate the effect of a viaduct on daylighting and deciding how to deal with it belongs to environmental impact assessment according to the definition given above.