Paryushan is the most important Jain festival for both lay Jains and monks, especially in the Śvetāmbara tradition. It is a period of fasting, confession, scriptural study, and reflection, and it culminates in Samvatsari (confession day). Oli (the Shvetāmbara 9-day fasting-celebration) is also significant but is considered a separate, recurring ritual of the year, observed twice a year and focused on celestial worship of Tirthankaras. In short, Paryushan is the primary festival; Oli is a major, regular ritual within the year. Digambar Jains have their own corresponding observance (Dashalakṣaṇa-parva) with different texts and emphasis, and they mark Mahavira’s nirvana as part of Diwali as well. ( britannica.com, jainworld.jainworld.com)