Do India really need a National language?

I am not writing this to justify Hindi should not be the National Language. Because it is not already. Its officially the Official language. So why does India require a national language ? Its because a Tamilian can fluently complaint to a Delhi Minister or a Maharashtrian to sell Jio sim easily in North east or a Tribal can greet a Punjabi Ecotourist like 'Kaise ho (How are you)' or every citizen starts understanding the meaning of each central government scheme or its that PM can address people in a bid to ensure 'The nation wants to know (what he speaks)'. I tried hindi and somehow learnt that sound 'gaha'. I faced this problem when I was about to sing a Hindi song in my company's culturals. But does it stop at reproducing 'gaha' or is there any more to it ? No, but can it be or should it be ? ...