Bura na mano, Holi hai! Don’t mind – it’s Holi! This is the unofficial chant of the annual national colour festival of India, and it sends a message: on this day, anything goes. This year, that day is 21 March. You might not have to mind your manners, but you do have to watch your step and beware of your back and head getting blasted with colours by anyone, including strangers.

Holi is a Hindu festival celebrating love, the arrival of spring and the victory of good over evil. It’s also a rollicking good time, one that has spread throughout the Indian subcontinent, even among non-Hindus, while gaining traction globally as well.

It traditionally involves rituals based on Hindu legends, but Holi is now a more relaxed event of music, dancing and the customary drink, bhang. A sort of milkshake made with cannabis, bhang is as big a part of Holi as mooncakes are for Mid-Autumn Festival in Hong Kong. The government gives the intoxicating concoction a pass, given its prominence in this widespread festival.

The main event of the day is colour-bombing everyone around you. The rule is to show no mercy – and expect the same from them. You could simply be walking down the street when a watercolour balloon bomb splashes on your head. No amount of scrubbing will save you from having a tinted head of hair for the next couple of days.

People often wear white clothing on Holi so that the colours – usually pink, yellow and green – show up better. These colours might land on you in powdered form, through water guns, water balloons or, if you’re small enough, a dunking in a water tank. An old belief is that the first person you colour should be someone you love or someone you are romantically interested in. So if you have a crush, Holi could be your moment.

Imagine a romantic comedy with a baking scene where the actors end up covered in flour: you’ll end your day looking like that but with lots of colours instead. All of this chaotic celebration happens with live drumming in the background and, as with any Indian festival, dancing. Almost all of India is given a day off for this frenzy, which ends with a family feast after everyone has washed and looks decent again – and after the effects of bhang have worn off.

Experience Holi for yourself: Mathura and Vrindavan, both cities near Delhi, have some of the biggest and most famous celebrations.