How can a large population be converted from a liability to an asset for the country?

By investment in human capital

For many decades in India, a large population has been considered a liability rather than an asset. But a large population need not be a burden for the economy. It can be turned into a productive asset by investment in human capital (for example, by spending resources on education and health for all, training of industrial and agricultural workers in the use of modern technology, useful scientific research and so on)