In Jainism, during the festival of Paryushan (also spelled Pajushan), "paani kaal" refers to the last time one can drink water before beginning a fast, especially for those undertaking an upvaas (complete fast). The specific time for paani kaal can vary according to local tradition, the sect (Shwetambar or Digambar), and the type of fast being undertaken.

Common Practice: For many Shwetambar Jains, paani kaal is observed at sunset on the day before the fast begins, or sometimes at least 48 minutes (one ghadi) before sunset. After this time, all water and food intake is stopped until the fast is broken.

Hours Calculation:

• If sunset is at 6:30 PM, paani kaal would commonly be at 5:42 PM (48 minutes before sunset).
• For some, it's simply at the time of sunset.

Summary: Paani kaal typically ranges from 48 minutes before sunset up to the time of sunset itself. This means, from paani kaal to the next opportunity to drink water (after breaking the fast), the duration can be 24 hours or more, depending on how long the fast is kept.

It is always best to consult with your local Jain Sangh or spiritual teacher for the precise timing followed in your community, as customs may differ.