Antya pushkaras are from 31-07-2016 to 11-8-2016. Godavari pushkara comes after every 12 years. IF 12*12=144 years, then it is mahapushkara. But there is no scientific data to conclude the current pushakara is godavari maha pushkara.
Pushskara is coneived to be the auspicious time for Pithru Yagna like performing Pithru Shraaddha, Tharpana have been prescribed to do away with from Pithru Runa. It is widely believed and said that that Pithrus (fore-fathers) will descend on Earth during Pushkara days and will reside on the banks of Pushkara River longing for their off-spring to perform Pithru Shraaddha. This has been in vogue since time immemorial and even Avathara Purushas like Sri Ramachandra (Lord Sri Rama), Lord Parashurama are said to have performed Pithru karma. Performing Pushkara shraaddha, one will be bestowed with blessings from fore-fathers, peace and prosperity to the family.There is a belief that by performing reverences of ancestors they will be out of common facing problems in life related to marriage, progeny, health, poverty.
As per my knowledge (Its purely my opinion if wrong seniors pls correct me), there is nothing mentioned about reliving of fore-fathers from hell . I feel, the result will be in-muliple . For example, after death soul travels from body to hell, the shradda karma helps to makes the soul travel from earth to hell. That means if u do at pushkaras, soul wont starve for years.. / Feel of punishment may reduce. If they reborn in any other creature, it helps the creatures in other forms by materialstic or spiritual blessings..