Which primary factor was chiefly responsible for the steady decline in mortality rates in India following the year 1921?

The correct option is Advancements in healthcare services and public sanitation.

Explanation:

The year 1921 is widely regarded as the "Year of the Great Divide" in India's demographic history. Before 1921, India experienced stagnant population growth characterized by both high birth rates and high death rates due to recurring famines, widespread epidemics (such as plague, cholera, and influenza), and rudimentary healthcare infrastructure.

Following 1921, India entered the second stage of demographic transition, marked by a continuous and significant decline in mortality rates. Key factors behind this trend include:
1. Healthcare Advancements and Epidemic Control: Systematic medical interventions, introduction of immunizations, and better disease management effectively curbed mass outbreaks of fatal diseases like smallpox, plague, and cholera.
2. Improvements in Public Sanitation: Greater attention to public hygiene, sanitation initiatives, and safer water supplies lowered the transmission of infectious diseases.
3. Effective Disaster & Relief Operations: Enhanced food distribution and famine mitigation reduced starvation-related deaths.

Consequently, the primary driver for the sustained reduction in death rates after 1921 was the advancement in healthcare services and public sanitation.