'One child policy' is one of the measures to decrease the population size. This policy can be categorised under which of the following? 

Preventive Checks 

One child policy is an example of preventive check.
According to Malthus, humanity has only a limited ability to voluntarily reduce the growth of its population (through ‘preventive checks’ such as postponing marriage or practicing sexual abstinence or celibacy). Malthus believed therefore that ‘positive checks’ to population growth – in the form of famines and diseases – were inevitable because they were nature’s way of dealing with the imbalance between food supply and increasing population.