In Jainism, abstaining from water for a day is called "Nirjal Upvaas" (निर्जल उपवास). "Nirjal" means "without water," and "Upvaas" means "fast." This type of fasting is considered very austere and is usually undertaken during special occasions, such as Paryushan or on important Jain festival days. It is performed with the intent of self-purification and spiritual upliftment.