When you leave this body you are guided into another world by a set of Devas or Angels. Pururava, Vishvedeva - these are their names. They come and guide you from one level to another level.
Mahalaya Amavasya is the day when you remember all the departed souls and thank them and wish peace for them.
There is an ancient tradition in which the family members take a few sesame seeds and little bit of rice, and then they think of their ancestors and say, ‘May you be contented, may you be contented, may you be contented.’
They say this three times and then they drop the little grains of sesame seeds with some water.
The significance of this ritual is to tell the departed that – If you still have some desires in your mind, know that they are like sesame seeds. They are not significant, just drop them. We will take care of them for you. You be free, happy and contented! There is huge universe in front of you. The universe is infinite, so look forward and go; drop whatever is pulling you back.
This is called Tarpana.
Tarpana means bringing satisfaction and fulfillment to the departed. It is done to tell them to be contented and move further.
Water is the symbol of love. To give anyone water means giving love.
In Sanskrit, Ap means water and it also means love. And in Sanskrit someone who is very dear is called Apta.
So, in their memory, you give them water as a symbol of love and life and that is why this is called Mahalaya Amavasya.
On this day think of all your ancestors.
In Vedic tradition, three generations on the mother's side and father's side are remembered, and all others friends, relatives, and anyone who has crossed over to the other side. Think of them and tell them to be satisfied.
Usually in their memory, people also do some charity, by giving food to some people and to animals.
This is there almost in all the cultures of world. I was surprised to see that this is there in Mexico as well.
In Mexico, on 2nd November, every year people celebrate this.
Similarly, they do this in China as well. In the Chinese tradition, they have one day on which they remember their ancestors, and whatever was dear to the ancestors, they make that and offer it to them.
They do this in Singapore as well. Although Singapore is a very clean city, but one day in a year it becomes very dirty for a few hours because they celebrate this on the streets.
Do you know what they do? They make huge cars and homes out of card board and burn them on the streets so that it goes to their ancestors.
They also buy a lot of fake currency notes and burn them so that people on the other side get this offering and give blessings.
Almost all over the globe, from the ancient civilization, everyone practices this.
In Christianity also, there is a day called All Saints’ Day when the ancestors are remembered. On this day people go to the graveyard and pray for the departed.
This is also done just to remind oneself that life is temporary, and so many years these other people lived here and have now gone. We have come to this world and one day we will also go.
So you wish them peace and thank them. That is the main idea.
In India the ritual is all in Sanskrit and so people don't understand them. The pundits say something and then they ask you to do this and do that, and you just do it with faith.
That is not bad but it is good to do it with a little understanding.