What is World Spay Day?
World Spay Day is a day to shine a spotlight on spay/neuter as a proven means of saving the lives of companion animals, feral cats, and street dogs who might otherwise be put down in a shelter or killed on the street.
World Spay Day provides a unique opportunity for everyone who cares about animals to join together toward a common goal —a comprehensive global, united effort to end the euthanasia and suffering of companion animals.
Past events have included low- and no-cost spay/neuter clinics, providing life-saving veterinary services for low-income families, fundraisers to benefit spay/neuter programs, and educational efforts spreading the message about the importance of spaying and neutering pets.
(from official site)