If the Moon is not Sighted even after Fasting for Thirty Days

Q: Hil-15: What will happen when the sky is unclear and the moon cannot be sighted even after fasting for 30 days? Will Eid be celebrated or will a 31st fast be observed?

Answer: If the sky is unclear or overcast, the sighting of the moon will be established by the testimony of a trustworthy man or woman. However, if the moon is not sighted after 30 fasts, Eid will be celebrated and a 31st fast will not be observed. The same is stated even in the book Bihaare Shari'ah (Vol.5 Pg. 112), which is relied upon by people associated with Ridha Khan. And Allaah knows best what is most correct.

Fatawa Rahimiyyah vol.3