Something must be wrong here.
Why would Pakistan's population grow by 3% annually between 1998 and 2011 when India's population only grew by 1.6% annually between 2001 and 2011 ?
Either massive overcounting, or double counting, or Pakistan is really so poor that people want to have as many kids as in sub-Sahara Africa ...
Cultural differences - Muslims have larger families.
I know, but that cannot make up the difference.
I've been looking at India's Census data from 2001 and 2011 and even the Muslim regions of India that border Pakistan did not have more than 2% annual growth between 2001 and 2011.
And yet Pakistan has 3% annual growth ? That's really strange.
Another possibility could be that the 1998 Census was the flawed one and the 2011 Census is the correct (?) one ...
Different political attitudes as well. The Indian government and the governments of many Indian states have supported family planning, while the Pakistani government has not.