Mahalaya Amavasya or Pitru Amavasya is the No Moon day in Mahalaya paksha shraddh. In 2013, Mahalaya Amavasya date is October 4.
Pitru Amavasya falls during Ashwin month as per North Indian calendar followed in Uttar Pradesh, Madhya Pradesh, Bihar, Jharkhand, Chhattisgarh, Himachal Pradesh, and Uttaranchal. Mahalaya Amavas is the last day of Pitru Paksha, the fortnight dedicated to offer Shraddh rituals to dead ancestors.
In 2013, Mahalaya Amavasya is Bhadrapad Amavasya as per Marathi, Gujarati, Kannada & Telugu calendars. It is Ashwin Maas Amavasya as per North Indian Hindi calendar.
On Mahalaya Amavasya, Brahmin santarpana is performed on behalf of dead ancestors to provide them peace in their world. Hindus believe that Shraddh ritual performed on this Amavasya makes their dead ancestors free from all the sins they have committed when they were alive and provides them salvation.
In 2012, Mahalaya Amavasya date is October 15, 2012.
In 2012, Mahalaya Amavasya is Nija Bhadrapad Amavasya as per Marathi, Gujarati, Kannada & Telugu calendars. As there is Adhik Bhadrapad maas in 2012-2013 year, Nija Bhadrapad Maas Amavasya is considered as Mahalaya Amavasya.