What has changed? Fewer babies, as you might have predicted. Back in the early 1980s, the Indian woman used to give birth to an average of 4.5 children in her lifetime. That has dropped by nearly a half in the 30 years since. The total fertility rate, or TFR, dropped to 3.2 by the new millennium, and is now just about 2.4. This is not much above the internationally accepted "net reproduction rate", or NRR, of 2.1. For India, given its higher infant and child mortality rates, and also the skewed sex ratio (fewer women), the NRR should be a little higher than 2.1. So India's TFR may already have reached the much-desired NRR - or will do so in a year or two, well ahead of all forecasts.
This does not mean that population growth is about to stop; because of steadily increasing lifespans and also because more women are entering the child-bearing age than the number leaving it, the population will continue to grow for another three decades or more. But this growth is certain to be at a sharply lower rate than so far, and may completely stop a decade or so earlier than assumed till now. But the really startling byte in the statistics is that about a dozen states, accounting for close to half the country's population, are already at an NRR of less than 2.1, some of them being as low as 1.6 (which puts them in the same category as the ageing societies of Europe). The black side of this somewhat unbelievable statistic is that in some (not all) of these states, the very low TFR reported may be because millions of girl-babies are being killed at birth, and therefore not reported. Sanjeev Sanyal, global strategist at Deutsche Bank and a contributor to this page, has highlighted the drop in the TFR and related trends, and forecast that India's population will peak at 1,550 million, not the United Nations' figure of 1,700 million.
There are many consequences when the population stops getting younger. From now on, there will be fewer children entering the school-going age each year. Since primary school enrolment is virtually total, this means focusing not on more such schools but better ones. Meanwhile, even as the country's total population grows by perhaps 340 million in the period from 2001 to 2021, the total population under 15 will remain virtually static, at about 360-370 million. The entire addition to the population is being accounted for by those in the working age group (15-64; hence the much-talked-about demographic dividend) or by senior citizens. If the first demographic transition was the start of the population explosion after the 1921 census (when India's population was 251 million), the second transition has just started and will play itself out over perhaps three decades. Many of us should expect to live long enough to see India's population number peak and then start to decline.