Sheetala Ashtami (Basoda) Puja is dedicated to Goddess Sheetala and celebrated on Krishna Paksha Ashtami after Holi. Basoda is also known as Sheetala Ashtami. Usually it falls after eight days of Holi but many people observe it on first Monday or Friday after Holi. Sheetala Ashtami is more popular in North Indian states like Gujarat, Rajasthan and Uttar Pradesh.
According to Basoda customs families don't lit fire for cooking. Hence most families cook one day before and consume stale food on Sheetala Ashtami day. It is believed that Goddess Sheetala controls smallpox, chickenpox, measles, etc. and people worship her to ward off any outbreak of those diseases.
In Gujarat, the similar ritual as Basoda is observed just a day before Krishna Janmashtami and is known as Shitala Satam. Shitala Satam is also dedicated to Goddess Sheetala and no fresh food is cooked on the day of Sheetala Satam.