Step-by-step explanation:
In 1979, the Chinese government instituted a one child policy to try to control its rapidly increasing population. The government had already enacted an aggressive family planning policy and fertility rates were already dropping sharply. Simultaneously there were major market-oriented economic reforms, which launched very rapid growth and migration to cities, which also reduced fertility. The policy was highly controversial in rural areas (where children were an asset in farm work) and interfered with the strong demand for sons. It helped solve the problem of famine, but by 2010 was leading to a major demographic disaster, with too many old retired people supported by too few workers. China returned to a two-child policy in 2015. Controversies are ongoing.