Answer

If you mean the Shvetambar observance, Paryushana in 2021 ran from Friday, September 3 to Friday, September 10, 2021, with Samvatsari on September 10. ( msjs.org.au)

Explanation

Paryushana dates can vary by Jain sect and local panchang. The Victoria Parliament notes that Shwetambar and Digambara Jains observe Paryushana on different date ranges. ( parliament.vic.gov.au)

Takeaway

So the commonly cited 2021 Shvetambar Paryushana dates are September 3–10, 2021. ( msjs.org.au)