Usually the airlines in India will offer promotions during the offpeak seasons. With indian intelligence and security agencies ruthless in harassing, persecuting and torturing unmarried people in India, most middle class and wealthy people are married and have children.
So unless their children are grown up, most married indians are taking holidays during the summer and winter vacation for their children, so that the children do not have to miss school. Single indians can take their holiday any time of the year.
Hence airline ticket prices are usually higher during the vacations for schools in April, May, June, during the winter holidays around Diwali, Christmas, during October November, December. During the offpeak season prices are usually lower, and there are many promotions.