Step 1: Understanding the Concept:
The question asks for India's rank in world population based on data from the year 2011.
Step 2: Detailed Explanation:
\[\begin{array}{rl} \bullet & \text{According to the Census of India 2011, India's population was approximately 1.21 billion.} \\ \bullet & \text{At that time, China was the world's most populous country.} \\ \bullet & \text{Therefore, in 2011, India held the position of the second most populous country in the world.} \\ \end{array}\]
Step 3: Final Answer:
In 2011, India's position in the world in terms of population was second.