INDIA has been growing steadily richer in recent years, but it still has more malnourished people, especially children, than any other country. A big, nationwide study from 2005 and 2006, the National Family Health Survey (NFHS), found that 42.5% of children under five years old were underweight. The region with the next highest proportion of underweight children is Africa, with an average of 21%. Another measure of malnutrition is stunting, when children are unusually short for their age. Again, India's problems were shown to be unusually bad.

Now comes some good news. In 2013 and 2014 the UN agency for children, Unicef, and India's government conducted a new study called the Rapid Survey on Children (RSOC). The purpose was to gather up-to-date figures to use in the interim before the next big NFHS survey, which is under way. The RSOC report has unfortunately not been published, but The Economist obtained a copy.

It points to some striking national trends. For example the proportion of underweight children has fallen from 42.5% a decade ago, to just under 30% now. There have been similar improvements on stunting, wasting and other measures of malnutrition. The national immunisation rate has risen and the rate of open defecation is down from 55% of households to 45%.

Really interesting, however, is the breakdown of results by state, presented here. By and large social and health indicators across India follow predictable patterns. In states with higher incomes, those nearer the coast and farther south, most health indicators are better. Typical high achievers are Kerala and Tamil Nadu. In landlocked states, poorer ones and in the north, social and health results are usually worse. Notorious backward states include Bihar and Uttar Pradesh. North-eastern states are often outliers, both poor and landlocked but often with high rates of literacy and better health.

Results from the RSOC mostly bear out these trends. Everywhere has seen a reduction in the share of underweight children and in stunting. But it is striking that on occasion higher incomes do not correlate with the biggest health gains. Maharashtra and Gujarat are both states with relatively prosperous people, but Maharashtra's nutrition levels are better than Gujarat's. This is also true for rates of immunisation and of open defecation. It appears that Maharashtra's government has put more emphasis on tackling nutrition problems, for example among its adivasi, or tribal, population.

Two crucial factors are worth looking at. Lower rates of open defecation correlate well with reduced malnutrition. When children live and play in clean environments they are less likely to be infected with parasites that make it hard to absorb nutrients. And states that focus on helping girls and young mothers probably do better at breaking long-term cycles of malnutrition. Where teenage girls have a low body-mass index there seems a greater likelihood mothers will give birth to undernourished children. Proper nutrition for girls and women should be a priority.

Download data for 15 indicators here.

The original RSOC files—for each separate state and India as a whole—are available to download here (note: large file).

Read further on this story from this week's issue here and here.