The year known as 'Year of the Great Divide' with regard to population growth in India is

1921 is known as the 'Year of the Great Divide' in India's demographic history because it marked the point where India's population growth rate transitioned from stable/slow growth to rapid growth. Before 1921, both birth rates and death rates were high, keeping population growth low. After 1921, death rates declined due to improved public health while birth rates remained high, leading to population explosion.