Holi also called the Festival of Colours, is a popular Hindu spring festival observed in India,Pakistan, Nepal,Bangladesh, and countries with large Hindu diaspora such as Suriname, Guyana, South Africa, Trinidad, the UK, Mauritius and Fiji.

In Nepal, Holi is regarded as one of the greatest festivals. Everyone celebrates it regardless of the religion. People walk down their neighbourhoods to celebrate Holi by exchanging colours and throwing and splashing water to each other. One of the most famous activities is throwing water balloon to each other also called Lola (meaning water balloon). Also a lot of people mix 'bhang' in their drinks and food as done in Shivaratri. It is believed that the combination of different colours played at this festival take all the sorrow away and make life even more colourful .

Source: Wikipedia