Panchang Bhed on Fasting: Aja Ekadashi Fasting gives one salvation, on this day Tulsi worship and donation is a tradition.

As there is a gap in the astrological calculation, Ekadashi will be celebrated on August 22 and few places on August 23, Shri Krishna told Arjuna about this Ekadashi, only by listening to the story of this Vrata can one get the fruit of Ashwamegha Yajna.
Ekadashi of Shravan month is called Aja or Jaya Ekadashi. By worshiping Lord Vishnu with Vrat or fasting on this day, one can get the fruit of Ashwamegha Yajna. Along with this, there is a tradition of Tulsi Puja and its donation on this day. So that every type of sin committed knowingly or unknowingly can be removed. There is also Panchang Bheda regarding this date. In many places Ekadashi Vrat will be observed on 22nd and in few places on 23rd August.
The meaning of the name of this Vrata
By fasting on this Ekadashi one gets moksha so one does not have to be born again. That is why it is called Aja. By performing this vow, King Harishchandra was victorious and regained his kingdom. That is why it is called Jaya Ekadashi.
Aja Ekadashi Vrat Katha
Shri Krishna told Arjuna about the rituals and importance of this Ekadashi Vrat. He told Arjuna that only by listening to the story of this Aja Ekadashi Vrat which falls in the month of Shravan with devotion, will one get the fruit of Ashwamegha Yajna. Also all kinds of sins are removed.
Shrikrishna says that in the Puranic period, Sriram’s descendant Chakravarti became King Harishchandra in Ayodhya. He was famous for his honesty and integrity. The gods tested him. So the king saw in his dream that he had donated his kingdom to sage Vishwamitra. In the morning indeed Vishwamitra told him that you have given me your kingdom in a dream. After that, King Harishchandra gave the entire kingdom to Vishwamitra after observing the Satyanishtha Vrata.
King Harishchandra had to sell his wife, son and himself due to the fruits of previous birth karma to pay Dakshina for charity. Harishchandra was bought by a man who cremated people in a crematorium. Then the king became a servant of a Chandal. He worked to take the shroud, but did not leave the side of the truth even in the work of this time of trouble.
After many years of doing this work, he felt very sad about his bad karma and started looking for a way to get rid of it. While they were sitting in this worry, Gautama Rishi arrived there. Harishchandra told him his grief.
Maharishi Gautama was also saddened by this and told the king that you observe a fast and night vigil on the Ekadashi of Vada Paksha in the month of Shravan. It will remove all sins. In due course the king fasted on this Ekadashi. So his sins were removed and he got back his dead son and his kingdom too.