New Delhi, Jul 11 (IANS): India's four largest so-called BIMARU states -- Bihar, Madhya Pradesh, Rajasthan, Uttar Pradesh -- have been showing a steep rise in population despite effective methods of birth control in primary health care centres there, a brief by an NGO on World Population Day said Monday.

"Nearly 15 million women, mostly belonging to the 'bottom of the pyramid' in the four large North Indian states of Uttar Pradesh, Rajasthan, Madhya Pradesh and Bihar do not access available methods of family planning," said Devendra Kishore, professor of population programme management at the Management Institute of Population and Development (MIPD), in the brief.

The study depicted a contrast between northern states and southern states that have shown signs of population stabilisation.

"Southern states of Tamil Nadu, Kerala, Andhra Pradesh, Karnataka have been able to achieve the replacement level fertility, meaning a couple having only two children has kept the population growth almost stable," added Kishore.

The replacement rate in the region has been 2.1 children per women, said the brief, primarily based on the census statistics of 2011.

"Northern states have a long way to gap before they achieve the desired target. And that is a cause of concern," Kishore said in the brief.

World Population Day is aimed at increasing people's awareness on population issues such as importance of family planning, gender equality, poverty, maternal health, and human rights.

The brief indicates India's population will grow by 16-17 million annually in coming decades since more than 50 per cent of the population is in the reproductive age of 15-49 years.