It should be noted that the fertility rate is sort of an abstraction of what people would intuitively think of from the name. Fertility rate is the average numb

It should be noted that the fertility rate is sort of an abstraction of what people would intuitively think of from the name. Fertility rate is the average number of children a female would have if she experienced the exact current age-specific fertility rates for her entire lifetime. So add the current expectation value of kids at 18 + at 19 + at 20 ... The measure also assumes women all survive the entirety of their reproductive life. For a developed nation where mortality before old age is low and fertility rates have been reasonably constant for an extended period of time, total fertility rate should be close to the real average. Unfortunately, this measure breaks down in developing nations where mortality is non-trivial and reproductive behaviors are actively shifting. For example, if you have a large cohort that is delaying having kids until an older age, then in the short term the fertility rate at their current age range will sharply decrease, but the fertility rate of the older age range won't go up until they actually age into it, leading to a few years of fertility rates being inaccurately low, and then eventually a sudden increase. This is known as the Tempo Effect. It's also worth pointing out that the replacement level fertility depends on the mortality rate, 2.1 is a pretty good estimate for a developed nation, but it is often higher in developing nations. India's fertility rate has been consistently dropping for some time, as is typical for developing nations, so it's not surprising that they're getting a lower value now than 5 years ago, but this may be less qualitatively meaningful than the headlines may imply.