<p>Pollutant discharge is crucial for environmental management and numerous industry sectors. One method to assess how effectively the wastewater treatment techniques reduce pollutant levels is to analysis waste discharge concentrations. Recent research focussed on looking at the relationship between the fluid flow and the concentration of the contaminants released. The current study examines the unstable, incompressible, mixed convection of nanofluids through an infinite plate with the consequence of the porous material, pollutant concentration and thermal radiation. The partial differential equations (PDEs) and boundary conditions are reduced by non-similarity transformation to a collection of non-dimensional PDEs, which are later solved by employing the Crank–Nicolson finite difference technique. The effects of several dimensionless factors on the flow, temperature and concentration profiles are depicted visually. Some engineering coefficients are also examined. Major outcomes are, the velocity, energy and concentration profiles drop as the suction parameter rises. As the porosity constraints escalate, the velocity drops. The concentration declines as the Schmidt number enhances. The concentration increases as the local pollutant external source parameter and external pollutant source variation parameter rises. The temperature escalates as the heat radiation parameter rises. With an increment in the Grashof number, the velocity also rises. Several significant engineering processes, such as the preservation of food, manufacturing facilities, industrial waste, resources for petroleum gas extraction, nuclear power plants, insulating materials and packed-bed storage containers, rely on fluid flow via an infinite plate in the presence of pollutant concentration.</p>