India has surpassed China to become the most populous country, with a population of 1.4639 billion as of April. According to a UN report, India's fertility rate has fallen below the replacement level at 1.9 children per woman, compared to the needed 2.1 to maintain population size. This decline suggests that India's population may eventually decrease. Currently, 24% of the population is aged 0-14, 17% aged 10-19, and 26% aged 10-24, highlighting a young demographic.