Do we need a national language?

Dear Editor,
It is undisputed that India does not have a common language. The way Hindi is promoted seems by many as a threat to their respective cultural and linguistic identity and as an unwanted imposition onto them. Almost all are advocating for promoting their own language and literature. I am also one of those advocating for preservation and promotion of indigenous cultural identity. But, with due respect, I differ in my perspective when it comes to Hindi.
I, in all possible terms accept that Hindi is the language of the Norths. I also accept that Hindi is alien and a foreign to other people other than the northern people. But does it mean we must not have a common language? Preserving ones’ own language is different and having a common language in a nation so diverse in language, ethnicity, culture, colour etc. Having a common language is like a common rope which binds different pieces together. If anyone is against a common language, I firmly believe that the person is pervaded by ideas antithetical to the idea of Unity in Diversity.
A common language will be a cure, up to some extent, to the plague of regionalism: identifying oneself as Bengali, Assamese, Malyali, Tamil, Kashmiri, Bihari, Jat, Gujrati, Gujjar, and Bhil. We are Indians and we are one. To promote the spirit of nationalism (please do not start a debate questioning the admissibility of India as a nation), we ought to have a national language. Adopting a national language is not a threat to the indigenous languages. Arunachal Pradesh is a perfect example where we have adopted Hindi so well, but not at the cost of individual indigenous languages. We have adopted Hindi to communicate, adopted English in official writing, learned Assamese which is the neighbouring state’s language, all these while promoting and preserving our own local dialect.
India does not have a national language as of now. But if the idea of United India is to survive, it ought to have a common language which can be a national language. To enjoy the sweet fruit of United India, all must adopt the idea to develop a common language and learn that language even if superficially at market level. And what other language would suit more than Hindi as of this date? Sanskrit? Bangla? Tamil? Malyalam? Urdu? Punjabi? Odiya? Naga? Manipuri? Mizo? A tribal dialect? Andamani? Nicobari?
I request the fellow readers to explore what other language can be projected as a national language. And also find answer to the question whether promoting Hindi as the national language would really be detrimental to our linguistic or cultural identity? Whether we need a national language or not?
Ojing Megu, Itanagar