Mahalaya is one of these pakshas or phases of the pitru paksha. The Mahalaya falls on a no moon day and is also called the Mahalaya Amavasya. It is a tradition in India to offer food to their ancestors in this time. It is believed that if this is not done, then soul of the person will remain unsatisfied after death.
There is also a story in mythology about King Karna who did not offer any food to his ancestors while he was alive so when he died and was transported to heaven, despite his other good karmas he was not offered any food
There is another story which relates the mahalaya festival to Goddess Durga. The mahalaya is said to be the time period when the Goddess Durga killed the asuras. The Bengalis consider this day very important and it is still celebrated in many parts of Bengal. Plays are performed where the Goddess Parvati in the form of Durga where She kills the asuras and brings peace in the world.
This year it will be held on 19 September 2017 . So you can visit Kolkata this time annd can also stay during the Greatest festival of Bengal .."Durga Puja".
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