How can we compare the status of Urdu in Pakistan, with the status of Hindi in India before and after 1971 (the split of Pakistan)?

The Internet says that Urdu is the national language of Pakistan, but Hindi is not the national language of India. However, practically, both of them are the lingua franca in their respective countries.

How are they dissimilar according to the constitutions of their respective countries?

Note:

I am comparing Pakistan and India. I am comparing Urdu in Pakistan with Hindi in India.

I am not comparing Urdu and Hindi in India. I am not comparing Urdu and Hindi in Pakistan.