That means China's old-age dependency ratio (which compares the number of people over 65 with those aged 15 to 64) will soar.

ECONOMIST: Demography

In rural areas the dependency ratio will rise far more steeply than in cities as young people move out and the elderly stay behind.

ECONOMIST: The consequences of an ageing population

Its dependency ratio the proportion of children and old people to working-age adults is one of the best in the world and will remain so for a generation.

ECONOMIST: India's economy

Across Europe, the dependency ratio of older people (aged 65 and over) to those of working age (15-64) will double from one-to-four to one-to-two by 2050.

ECONOMIST: Economics focus

India's medium-term growth outlook is positive due to a young population and corresponding low dependency ratio, healthy savings and investment rates, and increasing integration into the global economy.

FORBES: India