Answer

Ayambil Oli is observed twice every year:

• Chaitra Ayambil Oli – begins on Chaitra Sud 7
• Aso / Ashwin Ayambil Oli – begins on Aso Sud 7

It continues for 9 days, ending on Sud 15 / Purnima.

Explanation

In Jain tradition, Ayambil Oli is a sacred period of तपस्या, especially connected with devotion to the Navpad:

• Arihant
• Siddha
• Acharya
• Upadhyay
• Sadhu
• Samyag Darshan
• Samyag Gyan
• Samyag Charitra
• Samyag Tap

During these 9 days, many Jains perform Ayambil tap, eating simple, tasteless food once a day, without spices, oil, ghee, milk, curd, sweets, fruits, or green vegetables, according to their tradition and capacity.

Takeaway

Ayambil Oli starts on Sud 7 of Chaitra and Aso/Ashwin months every year.