The eleventh day (ekadashi) of the dark (waning) half of the
lunar month of Ashadh (June–July) is a religious celebration.
This, like other eleventh-day celebrations, is devoted to
the worship of Vishnu, especially in his avatar as Narayana.
Most Hindu holidays have mandated ceremonies, which
generally include fasting (upavasa) and devotion, and frequently promise
particular rewards if performed faithfully.
Giving presents to needy brahmins is the recommended
activity on this day; following the festival sincerely takes away the sin of
chopping down a pipal tree (ashvattha) and also brings one birth in heaven.
You may also want to read more about Hinduism here.
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