'Development challenges will become more difficult as population increases'

.52 billion by 2036 (up by 25 per cent with reference to 2011).

Referring to the delivery of basic services, he said the country was facing many challenges with 20 per cent of the population below the poverty line and an equal proportion being illiterate.

Calling for the revival of India's age-old joint family system, the Vice President said, "Our family system must serve as a model for other countries to emulate."

Naidu called for equipping the elderly population with new age skills so that they may lead fuller professional lives and keep contributing to nation building.

Expressing concern that India has been grappling with a skewed sex ratio for a long time, Naidu said that the sex ratio was a silent emergency and had serious consequences that will adversely affect the stability of our society.

He said "We must also ensure adequate reservation for women in the Parliament and all state legislatures and appeal to all the political parties to arrive at a consensus at the earliest on this important issue."

"Country's progress will be hampered if women are not empowered politically," Naidu added.

( With inputs from IANS )