Eid al-Fitr is on the first day of the month of Shawwal (Islamic Calendar) and marks the end of Ramadan (month long fasting) and the beginning of a feast that breaks the fast. As mentioned above, the holy month of Ramadan ends with Eid, and so does the period of fasting from dawn to dusk.
Muslims thank Allah for the holy Quran, which was revealed to Prophet Muhammed on Laylat al-Qadr, one of the odd-numbered nights during the last ten days of Ramadan. For the unversed, fasting (Sawm) is one of the Five Pillars of Islam, and hence the significance.
Wishing Happy Eid to all from Agastya Family.