Detailed Instructions: You are given a passage. You need to construct a question about the information present in the passage. Construct a question in such a way that (i) it is unambiguous, (ii) its answer is the whole paragraph. Avoid creating questions that can be answered correctly without actually understanding the paragraph.
Q: First of all Hindi is not our (India's) single national language. There exists no such thing in our constitution. Languages in our constitution is devided into two categories. Namely Official languages (Central administrative)& Scheduled list of languages for official use.

Official languages are Hindi and English

Another 22 regional languages for official use.

Only around 40% of Indians speak Hindi as mother tounge but nearly 70% can understand Hindi. And that's hardly a criteria for "Naional Language".
A:
why was hindi declared as national language of india?