Why is Eid Al Fitr celebrated on different days?

Related questions

1. What is the significance of Eid Al Fitr?
2. How long is Eid Al Fitr?
3. What is Fitrana amount?
4. What do you do in Eid Al Fitr?
5. Who can receive Zakat?
6. When should I pay Zakat Fitr?
7. How did you celebrate Eid?
8. Do I have to pay zakat if I am in debt?
9. What is the purpose of Eid Al Fitr?
10. Do Shias celebrate Eid ul Fitr?

Tags

1. #based
2. #means
3. #begins
4. #ramadan
5. #which
6. #marks
7. #first
8. #celebration
9. #evening
10. #lunar
11. #shawwal
12. #signals
13. #breaking
14. #calendar
15. #month
16. #festival