Answer:
Hindi was identified as the national language by the Indian constitution.
Step-by-step explanation:
The only correction the declaration needed was the addition of the article "the" before the "national language." This correction was necessary because the article should specify and determine the title received by the Hindi language, as this is a specific and well-established title.
It is important to note that the article "the" is used to determine the precise form of the noun that is related to it, which in the case of the sentence shown in the question above is the word "Hindi."