India’s population has grown to 1.21 billion, second to only China, according to new census data. And despite a decade of slower population growth — it was 17.6 percent from 2001-2011, down from 21.5 percent in the 10 years before that — India still gained 181 million new people over that period, roughly the entire population of Pakistan. The government’s efforts to improve conditions for Indian women seemed to be borne out in some of the data, including an increase in female literacy that was higher than the country’s overall improvement, up about 9 percent to a nationwide literacy rate of 74 percent. But Indian officials expressed alarm about one statistic: the ratio of young girls to young boys (counting those 6 years or younger) fell over the past 10 years, from 927 girls per 1,000 boys in 2001 to 914 per 1,000 in 2011. That raised worries that despite laws to prohibit it, many families are still using abortion to ensure that they have sons.