Question

What is the main purpose behind celebrating holi

Answer 1

This is just for the arrival of a new season...enjoying and welcoming summer...

Answer 2

Holi's different celebrations come from various Hindu legends, although one is widely believed to be the most likely origin.

In it, the celebration's name refers to Holika,  the sister of the Hindu demon king Hiranyakashipu. The demon king was granted immortality with five powers:

He could be killed by neither animals nor humans
He could be killed neither indoors nor outdoors
He could be killed neither during the day nor at night
He could be killed on neither land, water nor air
He could be killed by neither projectile nor handheld weapons

When his immortality turned him evil and he began to kill anyone who disobeyed him, his son, Prahlad, decided to kill him. When the king found out, he asked his sister Holika for help; in their plan she would wear a cloak which stopped her from being harmed by fire and take Prahlad into a bonfire with her.

However the cloak flew from Holika's shoulders while she was in the fire and covered Prahlad; he was protected but she burnt to death.

In the legend, the Lord Vishnu then appeared to kill Hiranyakashipu by sidestepping his five powers.

He took the form of Narasimha, who was half-human and half-lion; he met him on a doorstep, which is neither indoors nor outdoors; he appeared at dusk, which is neither daylight nor dusk; he placed his father on his lap, which is neither land, water nor air; and he attacked him with his lion claws, which are neither projectile nor handheld weapons.

While Hiranyakashipu and Holika came to represent evil, Vishnu and Prahlad came to represent good. The story shows the victory of good over evil, which is why it is tied to the festival.

The other most popular origin of the festival is the legend of Krishna. The Hindu deity, embarrased by his dark blue skin, told his mother he was worried his love Radha would not accept him. She told him to colour Radha's face whatever colour he wanted; when he did, they became a couple.