In Jain Dharma, there is no specific scriptural rule that you must boil water for a ritual reason. Boiling water is mainly a hygienic practice that many people adopt to keep drinking water pure and safe. Here’s the Jain perspective in simple terms:

• Purity and harmlessness: Boiling water reduces germs and makes water cleaner, which aligns with the Jain emphasis on cleanliness and avoiding harm to living beings through contaminated water.
• Health and mindfulness: Clean water supports a healthy body, which helps a person practice vrat, meditation, and daily discipline more steadily.
• No strict sect difference: There isn’t a formal Digambar–Shwetambar difference mandating boiling water for religious reasons; it’s a practical habit you may choose for personal hygiene.

If you intended a specific regional or community practice by the word “athai,” the meaning could vary by place. In that case, a little more context about where or how you’ve heard the term would help me give you a precise Jain interpretation.