Why do people put a blue pumpkin on their porch steps?

People place a blue pumpkin on their porch steps to signify that they are participating in the "Blue Pumpkin Project," which raises awareness for children with autism and other special needs. The blue pumpkin serves as a visual cue for trick-or-treaters and their families, indicating that the house is inclusive and welcoming for those who may need additional understanding or accommodations during Halloween. This initiative promotes a more inclusive environment for all children during the festive season.