In this paper, we present a nonlinear mathematical model to study the removal of pollutants from the atmosphere of an industrial city through rainfall. The model incorporates four interacting variables: the number density of raindrops, the concentration of pollutants, the depletion of raindrops, and the removal of pollutants. The behavior of these variables is described by a system of nonlinear differential equations. Our analysis shows that if pollutants are emitted into the atmosphere instantaneously, they can be completely removed by rainfall. However, when pollutants are emitted at a constant rate, the model demonstrates that, under certain conditions, they can still be washed out of the atmosphere, with the remaining equilibrium concentration largely dependent on factors such as the growth rate of raindrops and the pollutant emission rate.