LydiaJJ, Actually the Festival Holi is more from northern India,it's celebrated in all over India but it's more famous from North.There the many places where it can be celebrated but the most famous place for Holi festival is a Mathura,(Uttar pradesh state),but that's too too busy and it's mostly known among the spirituality lover people,groups,societies & very-very religious Hindus go there.In many other parts of northern India it's very well celebrated and enjoyed very much.The most recommendable place for this event is Rajasthan,which is very well known for it's traditions,cultures,hospitality of the people,peaceful ambiance and colors.It's people are known as one of the India's most sympathetic and warm welcome & cheerful personalities all over. To enjoy any festival and the visits this is the most preferred place but not that touristc,(except some places like Jaipur,the capital.),to celebrate Holi festival Jodhpur and Jaisalmer are the place for enjoyment at it's fullest,Jodhpur is quite populated,Jaisalmer is the best place so far.As it's very small and it has familiar ambiance to celebrate any festival,There is desert also at the same time for adventure trip spending overnight in the desert under millions of stars.You can go for Jaisalmer photos.It's little far from Delhi but it has direct train from Delhi and this can be discovered in less then a week time also with the Golden triangle trip with Tajmahal.
Regards
M.Nayak