Solution:As per Census 1991, West Bengal was the most densely populated State of India, whose population density was 709 persons per sq. km. The population density of Arunachal Pradesh was 10 persons per sq. km as per Census 1991, which was lowest in India.The population of Uttar Pradesh was 11.1 crore in the year 1981, which had become 13.9 crore in the year 1991, that is during this period, there was a 25.22 percent decadal increase in the population of Uttar Pradesh. Hence all the Statements were correct during the question period.
As per Census 2011, Bihar (1106 persons per sq. km) is the most densely populated State of India and Arunachal Pradesh (17 persons per sq. km) is the lowest population density State of India.