Step 1: The Primary Cause: One-Child Policy.
The most significant reason for the sharp decline in China's population growth was the implementation of the One-Child Policy in 1979. Unlike India's voluntary family planning approach, China used strict regulations and incentives to limit population growth. Additionally, rapid urbanization and a focus on female education naturally led to lower fertility rates.
Step 2: Economic and Social Consequences.
The immediate impact was a reduction in the "dependency ratio," as fewer children meant more resources could be diverted toward infrastructure and industrial growth. This helped China achieve rapid economic expansion and higher per capita income. However, in the long run, this has led to a "demographic crisis" characterized by a rapidly aging population and a shrinking youth workforce, which now poses a threat to future economic sustainability.