In India census is held regularly every ________ year.

Correct option is B

India held the census regularly every 10 years.
 Last census was conducted in 2011
 Census conducted by the Office of the Registrar General and Census Commissioner of India
 1st census was conducted by – Lord Mayo
 1st complete census was conducted by – Lord Ripon
 Most Populous State of India – Uttar pradesh
 Least Populous State of India - Sikkim