How Hindi became the national language of India?

I have little to contribute to this debate except to point out to Neqitan that Gujarati and Oriya are not Dravidian or Southern languages. Both are Indo-European languages related to the languages of the North; Gujarati, spoken in the Western state of Gujerat, to the North of Bombay, is closely related to Hindi, Punjabi, Marvadi and Marathi, whilst Oriya, spoken in the Eastern state of Orissa, is related to Maithilī, amese, and Bengali.