Which of the following states recorded decrease in its population in 2011…

A state's decadal population growth rate is calculated as ((population in the later Census − population in the earlier Census) ÷ population in the earlier Census) × 100. Because births and in-migration normally outweigh deaths and out-migration over ten years, most Indian states recorded a positive growth rate between the 2001 and 2011 Census — a negative rate is the rare exception.

Nagaland is the only state in the table with a negative entry — official Census of India records and Nagaland's own state Statistical Handbook both confirm its population fell from 19,90,036 in 2001 to 19,78,502 in 2011. Bihar, Manipur, and Uttar Pradesh all grew substantially over the same decade, so Nagaland is the state that recorded a decrease.