‘Shradhs’ are part of the Vedic culture and cater to the specific needs of ancestors
The soul incarnates into a physical body which is made up of the five elements in various permutations and combinations, reincarnating birth after birth depending on the kind of karmas that one does in a lifetime. Certain souls do not reincarnate, either because they are finished with their karmic cycle of the the ‘Prithvi lok’ or because they are stuck in a different dimension of existence and are unable to manifest in the human body, as their karmic balance is not sufficient to entitle them for human birth. These souls either remain suspended as energies and are called ghosts and spirits or they go to a different dimension of existence called the pitr lok or the lok of the ancestors.
Whatever dimension or level of existence they are in unless they have been freed from the cycle of birth and death, they need energy from their offspring to offset their karmic balance to enable them to reincarnate again.
‘Shradhs’ are an important part of the Hindu/Vedic culture and cater to these ancestors' needs. On these days the constellations are such that the gateways to the other dimensions open and they are allowed to visit the earth to meet their near and dear ones. These ancestors depend on their children and grandchildren to do good deeds in their name and to chant specific mantras, both these acts free the souls from bondages of these not-desired yonis or levels of existence. It is the basic duty of the family members to perform certain rites and do charity and ‘guardian’ in the names of their close ones, as only once you are in the human body can you do all this, once out - all is lost and you are dependent on others for your salvation and rebirth (if your karmas do not permit).
At present and age, the youth of the country has no idea about the power and efficacy of the Vedic sciences and the phenomenal knowledge of the Vedic ‘mantras’ and rituals, the present education system is to be blamed for this as it is completely based on what the colonial masters chose for us, they were fearful of the power of the Vedas and hence destroyed the gurukul system and ensured that we were taught redundant sciences and tweaked history to their advantage the purpose was so that the coming generations lose faith in their culture and follow the colonial masters blindly. The result that they wanted is visible today.
For the younger generations who might be thinking by now that this article reeks of Hindutva and is a fairy tale based on fiction, I would like to point out certain facts of history. In the ancient world, the main cultures flourishing around 4,000 years back were the Egyptians, the Mesopotamians, the Romans, the Mayans etc. and of course our very own culture. None of the present-day religions or schools of thought were present, except the Hindu religion and the Vedic thought. All the cultures are prevalent believed in the other world and traveling of the soul to other dimensions.
Scientists today accept that the ancients had a strong knowledge of mathematics, astronomy, chemistry and physics. The pyramids are aligned in the north-south direction and the shafts in them are pointing towards the three main stars of the Orion belt which the scientists of today say could be the birthplace of stars and human origin.
It is important to note that the Hindu culture is the only culture that predates all the other cultures and is still the largest practised religion, its mantras and practices are not mumbo jumbo but they are a gift of a highly advanced civilisation to the present day humans That's why it has survived till date.
(The is a spiritual guide and well-versed in ancient Vedic sciences of Yoga, Spiritual Healing and Yagyas; views are personal)