The Hindu ceremonial year is mostly based on a lunar
calendar, with twelve lunar months lasting around 354 solar days (as opposed to
the 365 days of our calendar).
Because of the difference between the lunar and solar
calendars, each lunar year starts eleven days earlier than the preceding lunar
year.
Because of the mismatch, the two calendars began to drift
more and more, to the point that "spring" celebrations may occur at
any time of the year.
It was solved by adding an intercalary month every 212
years—more specifically, every 32 months, 16 days, 1 hour, and 26 minutes.
This intercalary month may occur during any of the twelve
lunar months throughout the year, and it takes the name of the ordinary lunar
month before it.
The extra month is typically seen as a ritually harmful
period due to its peculiar nature, and one of its prevalent nicknames is
"impure month" (malamasa).
It is considered that during this month, one should not
start any new undertakings or execute any religious ceremonies whose timing is
uncertain and might be postponed, such as weddings.
Keeping religious fasts and offering charity (dana) are also
regarded to be particularly beneficial during this period.
Fasting and devotion are techniques to acquire heavenly
favor and protection, while generosity functions as a conduit for passing any
possible ill fate to the receiver.
Purushottama Mas is the additional month that occurs in the
lunar month of Ashadh, and it is primarily celebrated by followers (bhakta) of
the deity Vishnu as a time for devotion and other spiritual activities.
You may also want to read more about Hinduism here.
Be sure to check out my writings on religion here.
