Answer

In Digambar Jain tradition, Paryushan is called Das Lakshan Parva and it lasts for 10 days.

If someone is doing 16 Upvas, it usually begins 3 days before Das Lakshan starts and continues through the 10 days, often extending 3 days after, making a total of 16 consecutive Upvas.

Explanation

So the start date depends on the specific year’s Jain calendar and local sangh practice.

Generally:

• Das Lakshan Parva begins from Bhadrapad Shukla Panchami.
• 16 Upvas would typically start 3 days before that.

Takeaway

For the exact start date, please confirm with your local Digambar Jain temple / sangh panchang, because dates may vary slightly by location and calendar tradition.