Muslims, as a group, have a higher population growth compared to Hindus in India. The headlines told you that already. A state level analysis is, however, what one’d like to look at this instance. Cherry picking, for instance, Kerala’s lower growth in Muslim population compared to Bihar/Uttar Pradesh doesn’t do justice to the data.
A plot of Hindu and Muslim population growth rate — that is the annual population growth rate and not the absolute growth rate — against the total annual population growth rate for each state shows up thus.
Many of us would like to think this is explained by low levels of education and poverty among Muslims. But that too isn’t borne out by the data. The population of Scheduled Castes in each state has been growing at a much lower rate compared to Muslims. Both groups are disadvantaged and thus higher fertility owing to those factors doesn’t explain the premium that Muslim population growth rate seems to have.
The Muslim growth rate across states seems to be less explained by that particular state’s local factors, as suggested by a lower R squared value. Whereas, the Hindu growth rate has a high R squared and seems to have settled into a pattern. This is somewhat expected since the total population in a Hindu dominated society will be explained by Hindu population growth. But the difference in value is there for us see. The data point that explains this best and is perhaps the most surprising part is: the annual population growth rate of Muslims in Tamil Nadu/Maharashtra is higher than that of Hindus in Uttar Pradesh/Madhya Pradesh.
The other factor that explains the Muslim premium is: the far end of high population growth is where it converges with Hindu rates. But that’s after exponentiation in the Hindu rates; except Bihar most states have settled into lower rates of growth.
The Hindu right may exploit this for conspiracy theories. But that’s no reason for the rest of us to pretend socio-economic factors that result in lower fertility have an equal effect on population growth rates of Muslims and Hindus. They don’t seem to.
 – The data of Scheduled Caste population growth is so uneven among states that something seems wrong with it. That’s why I haven’t plotted it. Perhaps migration explains that. But I wasn’t sure.
 – All data from Census. If you have trouble getting 2001 data for you analysis, please leave a comment.
 – This does not change the relationship between fertility and female education levels as argued here. But as every example problem in basic arithmetic class taught us, population grows exponentially.