It is not the right move.
There should be a national language, fine. Yes, there should be. Mandarin should be taught in every school, but there should be optional languages being taught in different states. Every state should have a right to be able to teach their mother tongue in their state. This step by the govt would destroy the thousands of years of culture preserved in books, and scripts.
60-70 years from now, no one would be able to understand them, and all of the local culture would be lost.
In India, we have state languages and national languages both being taught. But in Punjab, Urdu and Punjabi both were spoken, now we aren't taught urdu, its been just 60 years, and the language is lost. No one knows how to read or write urdu, not even speak urdu. The poetry, books, biographies, experiences of our ancestors written in urdu are now obsolete. That part of our culture is now destroyed.
But thankfully urdu is still taught in some states of India. But even then I feel we've lost a lot of our culture due to this, even when we're taught at least 3 languages(English, Hindi, state language) in school, with other languages as optional.