According to the Census of India conducted in 2011, the least populated state in India is Punjab.

Option 1: Maharashtra has a considerably larger population compared to Punjab, so it is not the correct answer.

Option 2: Madhya Pradesh has a higher population than Punjab, so it is not the correct answer.

Option 3: Odisha has a higher population than Punjab, so it is not the correct answer.

Option 4: Punjab is the correct answer as it has the lowest population among the given options.

Therefore, the least populated state in India, according to the Census of India 2011, is Punjab.