Ashwin month (Ashwina maas) is the 7th month according to the traditional North Indian Hindu Hindi calendar. In 2011, Ashwin month begins on 13th September and ends on 12 October. The North Indian traditional Hindu calendar is followed in Uttar Pradesh, Himachal Pradesh, Uttarakhand, Bihar, Jharkhand, Madhya Pradesh and Chattisgarh. Mahalaya Paksha ( Pitru / Shradh Paksha), Durga Navratri, Vijaya Dashami (Dussehra) & Sharad Purnima Lakshmi Puja are the main festivals in Ashwin maas.
The first half (Krishna Paksha) of Ashwin month is referred as Shradh Paksha or Mahalaya Paksha. During this fortnight, Shradh rituals or Tarpan kriya to dead ancestors are performed. Mahalaya Paksh or Pitru Paksha ends with Mahalaya Amavasya.
In 2011, Krishna Paksha in Ashwin mahina begins on September 13 and ends on September 27. Ashwin Shukla Paksha begins on September 28 and ends on October 12 in 2011.
Durga Navaratri 2011 starts on September 28. Navratri during Ashwin maas is referred as Sharad Navratri, Sarada Navaratri or Maha Navratri. Durga Navratri begins with Ghat Sthapana or Kalash Sthapana. In 2011, the date of Ghat Sthapana is September 28. In 2011, Lalita Panchami is on October 1, Durgashtami is on October 4, Mahanavami is on October 5 and Dasara 2011 (Vijaya Dashami) is on October 6.
As per Andhra Pradesh, Karnataka, Maharashtra and Gujarat calendars, Ashwayuja masam 2011 begins on September 28 with Durga Navratri and ends with Ashwayuja Amavasya (Diwali or Deepavali) on October 26, 2011.