In the Śvetāmbara Jain tradition, the first day of Paryushan is marked by performing Pratikraman (a ritual of repentance and reflection) in the evening. Typically, the Samvatsari Pratikraman (annual Pratikraman) is performed on the last day (Samvatsari), but daily Pratikraman is also observed during Paryushan.

For Śvetāmbara Jains, the traditional time for daily Pratikraman is:

• Evening: After sunset, generally about 48 minutes after sunset (when it is considered night according to Jain time calculations).

On the first day of Paryushan, you should perform Pratikraman in the evening after sunset, following the prescribed schedule of your local Jain Sangh or temple. Many communities announce a specific time based on local sunset timings, so it is best to check with your local Jain center for the exact timing.

Summary:

• First day Pratikraman (Śvetāmbara): Evening, after sunset (about 48 minutes after sunset).
• Check your local Jain temple for the exact time.

If you need the timing for a specific city, you may consult your local Jain community or temple.