Hindus celebrate a number of festivals throughout the year. All the thirty days of the month, known as Tithis, are dedicated to the worship of one deity. Some months such as the Shravana and the Kartik are entirely dedicated to pujas and celebrations.
Aja Ekadashi is one of the Tithis considered to be very auspicious. Aja Ekadashi refers to the Ekadashi falling during the Krishna Paksha in the month of Bhadrapad. This year it will be observed on September 6, 2018. Every Ekadashi is dedicated to Lord Vishnu. Lord Vishnu, as well as Goddess Lakshmi, are worshipped on Aja Ekadashi day. It is observed as a fasting day. Lord Krishna had explained its importance to Yudhishthir. Krishna said that King Harishchandra had observed the fast as a result of which, his son regained his life, and the king regained his kingdom.
Devotees get up early and take bath during the Brahma Muhurta. The place for puja is cleaned, and some rice is spread on it. A Kalash is placed on the rice and then it is covered with a red cloth. Atop the Kalash, an idol of Lord Vishnu is placed. He is offered prayers after lighting a lamp and incense before him. You can offer all other items such as flowers, fruits and sweets to him. Use sandalwood paste as tilak.
The observer of the fast has to stay abstain from eating anything for the whole day. A whole night vigil is kept by all the devotees, where they sing devotional songs and hymns praising Lord Vishnu. The fast generally starts on the Dashmi Tithi, that is the day before the Ekadashi and the parana is performed after the sunrise of the Dwadashi Tithi, the day after Ekadashi.
Eating anything that is not satvik should be avoided from the previous day. However, some people observe this rule only from the evening of the previous day. Though many devotees refrain from eating or drinking anything throughout the day, the fast can also be observed by eating fruits by those suffering from health problems. Grains and honey should not be consumed on this day. Rice should be avoided by those not observing a fast as well.
The fast is observed in order to please Lord Vishnu. It is said that observing the fast gives salvation. All the sins of the past life are washed away by observing this fast. This fast also brings peace and prosperity in life. It is said that observing Aja Ekadashi day gives benefits equal to those of performing the Ashwamedha Yagna.