Positive check as envisaged by Thomas Malthus can be prevented if

Thomas Malthus, in his 1798 Essay on the Principle of Population, argued that population tends to grow faster than food supply. He identified two types of checks that keep population in balance with available resources:

• Positive checks - factors that increase the death rate, such as famine, disease, war, and epidemics. These are involuntary and painful ways by which population is reduced.
• Preventive checks - voluntary actions that reduce the birth rate, primarily moral restraint, which Malthus defined as delaying marriage and practising abstinence until one could afford to support a family.

Malthus argued that if people adopted moral restraint (the preventive check), population growth would slow voluntarily, and the painful positive checks of famine, disease, and death would be avoided. The preventive check prevents the positive check from operating.

Abolishing marriage is an extreme and impractical suggestion that Malthus never advocated. Reducing the death rate or building more hospitals would counteract positive checks after they occur rather than prevent them - and would actually worsen the population-food imbalance in Malthus's framework by allowing population to grow further.