Hanuman Jayanti is celebrated in honor of birthday of Lord Hanuman. He was the follower of Lord Rama and the son of Lord Vayu- the wind. Lord Vayu took him to the Lord Sun to gain moral knowledge, Vedic and arms. Whole of his life he remained celibate and served Rama with love and affection without expecting anything from him.
It is celebrated on the full moon day in the month of Chaitra that is in March or April by Hindu community. Lord Hanuman is also called as Bajrang Bali and Anjaneya.
On this day devotees go to temples of Lord Hanuman and apply vermilion on his idol.