There have been many questions raised regarding the difference of this two festivals and what makes them so distinctive from each other to have two different events to commemorate the dead that I have decided to do a bit more of research and to write about it in my own context.
As most of us know, Ching Ming was celebrated in the 2nd month whereas Ghost Festival/Yu Lan is in the 7th month in the Chinese Lunar calendar.
Ching Ming is when families would gather annually and make pilgrimages to the cemeteries of their dead ancestors.
They would clean their graves and offer incense/joss sticks, food (usually the favorite food of the dead), flowers and paper money.
They would burn the paper money and also other paper paraphernalia resembling items used by the living such as car, house, maid, clothes, or even tv and cell phones as the vendors get creative these days.
They are there to pay homage and respect to their dead ancestors and to fulfill their duties to clean the graves of their dead ancestors.
During this month which is after the Chinese New Year/New Spring, you will see most of the Chinese cemeteries/crematoriums crowded with people as all the families gather to pay their respects to their ancestors.
This is a tradition observed for centuries and I believe it originated from the teachings of Confucius on the importance of filial piety and remembering our ancestors and thus, all family members from near and far would travel back to reunite with their families and travel in huge groups to the graves.
The Hungry Ghost festival on the other hand, is when the dead comes back from Hell to visit their loved ones.
I remember one of my aunts used to tell me that during Ching Ming, the spirits are only allowed to roam the vicinities of their grave whereas during the Ghost month, they are allowed to go anywhere.
The rituals performed during this month is not only for your own loved ones/deceased ancestors, but also for the younger ones and even wandering spirits who may not be related to you.
Ching Ming, on the other hand focuses more on the ancestors, but Hungry Ghost festival is offered to all the spirits around; including your younger loved ones who have passed on.
During the Ghost month, there are also offerings to the King of Hell and the other guardians of Hell to ensure peace on the living earth, and also food and prayer offerings are made to the lost and wandering souls who had no one to tend to their graves, etc.
So, the main difference lies in the above reasons; and if that's not enough, during Ching Ming, the festival only lasts for 2-3 weeks compared to a whole month of the Ghost Festival.