It is not possible to have Eid on the same day all over the world but rather to be done on two days

Hadis Shareef mentions that, “You start Ramadan by sighting the moon and celebrate Eid also by sighting the moon. If moon is not sighted, then do complete the month in thirty days.” This very instruction of Hadis Shareef only indicates that it is not possible to have Eid on the same day all over the world but rather to be done on two days. Those in favour of Eid on a same day, lack knowledge on Shariat and geographical understanding. They should enhance their wisdom by accepting the guidance (Baiyaat) of a truly devoted Wali-Allah (friend of Allah) and through intense Dhikr and commitments.” Allah Pak Does say, “O you who believe! Enter perfectly in Islam (by obeying all the rules and regulations of the Islamic religion) and follow not the footsteps of Satan. Verily! He is to you a plain enemy.” Therefore, every Muslim should perform all their Ramadan, Eid and other ibadah after the instructions of Allah Pak and the guidance of Rasoolullah Swallallahu Alaihi Wa Sallam!