When growth of population is more in comparison to the resources of an economy then it creates unemployment.
(i) Rapid growth of population creates burden on land which results in increase in agricultural holdings and landless labourers.
(ii) Increase in population increases the burden on economic infrastructure, such as transport, communication, power, etc. which reduces the production and results in unemployment.
(iii) Rapid growth of population increase the number of non-earning dependants such as children and old age people.
Or
When the work available to a worker could not utilise his labour time fully or the income received from the work is not adequate, it is known as underemployment. And this underemployment has an direct relationship with the problem of population growth. Population in India has increased at a rapid rate, but the employment opportunities have not increased to that extent due to slow pace of economic development which leads to underemployment. If rate of growth of population is controlled, then problem of underemployment can also be controlled.