Ganda, also known as Gandanta, is a malefic period with reference to certain birth stars or nakshatra in Hindu astrology. Gandanta, refers, in Hindu predictive astrology to specific periods when six out of the twenty seven constellations (nakshatras), beginning with Ashwini, rule on a day. These periods extend to about five nadikas (or about two hours) according to the Hindu time measure. They are considered extremely malefic and no auspicious rite or ritual is to be performed. Besides, it is believed that children born during these periods would be greatly afflicted, as well as their parents and their family, with a few exceptions. The malefic period is at the beginning of Ashwini, Magha and Moola, and at the closing of Aslesha, Jyeshta and Revathi.
It is believed that a child born during the ganda periods will mostly be still born, and if it survives, it will be the cause of the death of its parents and even the extinction of its family.
However, there is an exception, which specifies that if ever a ganda-born male child survives, he will have a prosperous life. If a male child is born at gandanta sandhi or the junction of two ganda periods, which occurs at the end and beginning of two adjacent constellations and which together last for about four hours, as it happens in the case of the pairs of Revathi and Ashwini, Ashlesha and Magha, and Jyeshta and Moola, the factors mentioned above will be all the more effective. Thus the child will be stillborn and be the cause of undoing for the entire family; but if it survives, it will be extremely prosperous.
It may be noted that in line with the malefic periods related to the six asterisms mentioned above, malefic ganda periods are specified also for lunar days (tihi) and months.