The sex ratio of youths in India is "consistently decreasing" and it could go below 900 in next 15 years, a government report has suggested.

The report 'Youth in India 2017' publicised recently said reduction in sex ratio of youth is found to be much more than that of the overall population.

"A negative aspect of youth in India is that the sex ratio in youth population is consistently decreasing from 1991 onwards. It has come down to 939 in 2011 as compared to 961 in 1971 and is projected to decline further to 904 (World Bank projection) in 2021," the report released by Central Statistics Office said.

Quoting the World Bank projection, it said the sex ratio among youth could further decline to 898 by 2031.

The sex ratio among youth had declined to 945 in 1981 Census from 1971 while it rose marginally to 950 in 1991. In 2001, it was 940 and 939 in 2011.

The share of the youth population in total population has been continuously increasing from the level of 30.6% in 1971 to 34.8% in 2011, the report said adding, it is projected to decline and their share will come down to 31.8% by 2031.

"The percentage of male youth population to total male population follow the pattern of overall youth and was also on a steady rise till 2011. But the share of female youths to total female showed a slight decrease in 2001 which might have resulted due to declining sex ratio during this period," the report noted.

However, a "welcome shift" is the in the level of married women in younger age groups.

"The percentage share of currently married female in the age group 15-19 has come down drastically from 69.57 in 1961 to 19.47 in 2011 showing a welcome shift in the level of married women in younger age groups. Mean age at effective marriage for females in India has come up to 22.3 in 2014 as compared to 19.4 in 1995," it said.

It also said India has the “relative advantage at present” over other countries in terms of distribution of youth population.

As per India’s Census, the total youth population increased from 168 million in 1971 to 422 million in 2011. “India is seen to remain younger longer than China and Indonesia, the two major countries other than India which determine the demographic features of Asia,” it added.