The researchers developed a method to assess groundwater vulnerability in Kano Metropolis, Nigeria. They combined different parameters related to groundwater quality and pollution sources, using Geographic Information System for analysis. The study found that depth to groundwater, net recharge, impact of vadose zone, and groundwater confinement were the most significant factors affecting groundwater vulnerability in the area. By integrating additional pollution sources into the model, the researchers improved the accuracy of their assessments. This method could be useful for similar areas facing groundwater pollution issues.