“The festival signifies the victory of good over evil, the arrival of spring, end of winter, and for many a festive day to meet others, play and laugh, forget and forgive, and repair broken relationships, and is also celebrated as a thanksgiving for a good harvest,” Wikipedia says.
The festival has become popular with non-Hindus, as well, throughout Asia and beyond. My first experience of it was during an Indo-Caribbean celebration in Queens, New York, known as phagwah.
There, it involved a large gathering of people with bags of powdered dye, or sometimes watered down in a plastic bottle or water gun, basically dousing everybody in the vicinity with as many colors as possible. It was a fun place to take a camera, with several of the resulting images I made below.
The Daily Beast also published a slideshow highlighting some great images, titled “India and Nepal Greet Spring With Color.” Check it out — and happy Holi!