This year The Jewish festival Sukkot and the Hindu festival Sharad Purnima were on the same day.
The Hindu festival is a harvest festival celebrated on the full moon day.
The Jewish festival is also a harvest festival celebrated on the full moon day:
and the feast of ingathering, at the end of the year, when thou gatherest in thy labours out of the field.
(Exodus 23:16)
Thou shalt keep the feast of tabernacles seven days, after that thou hast gathered in from thy threshing-floor and from thy
winepress.
And thou shalt rejoice in thy feast, thou, and thy
son, and thy daughter, and thy man-servant, and thy maid-servant, and the
Levite, and the stranger, and the fatherless, and the widow, that are within thy
gates.
Seven days shalt thou keep a feast unto the LORD thy God in the
place which the LORD shall choose; because the LORD thy God shall bless
thee in all thine increase, and in all the work of thy hands, and thou
shalt be altogether joyful.
(Deuteronomy 16:13-15)
Howbeit on the fifteenth day of the seventh month, when
ye have gathered in the fruits of the land, ye shall keep the feast of
the LORD seven days; on the first day shall be a solemn rest, and on the eighth
day shall be a solemn rest.
(Leviticus 23:39)
So it isn't strange that we find 2 religions that celebrate a Universal phenomenon such as Harvest.
Is there a fundamental diffrance between the 2 religions in the way the celebrate it?
The Harvest is an event that repeat itslef every year.
It's an event that have nothing to do with the historical timeline so basicaly it's timeless.
Judaism take this timeless event and connect it with the historical timeline:
Ye shall dwell in booths seven days; all that are home-born in Israel shall dwell in booths;
that your generations may know that I made the children of Israel to dwell in booths, when I brought them out of the land of Egypt: I am the LORD your God.
(Leviticus 23:42-43).
