Observing fast on Eid-ul-Fitr and Ayyam-e-Tashreeq i.e. 10th to 13th of month of Zilhajja is prohibited (Haram). If any body started observing fast during these days it is not necessary to complete it.

Answer verified by

- Hazrath Peer-o-Murshid Mufti Syed Zameer Mahdi