India’s official statistics show no evidence of 20 million undocumented Bangladeshi migrants, despite claims by Union Minister Kiren Rijiju in Parliament. The Census data, including birthplace records and coverage errors, does not support such a scale.

How Undocumented Migrants Could Appear in Census Data

Undocumented migrants in India may respond to Census enumerators in three ways: avoiding enumeration, misreporting their birthplace, or truthfully disclosing it. Each choice leaves a distinct trace in the data, allowing for verification.

The Census records birthplace but not legal entry status, grouping citizens, visa-holders, and undocumented migrants together. This limits the data’s ability to distinguish between them, though it can still assess whether a population of the claimed size exists.

Coverage Errors and Census Omissions

Coverage errors occur when individuals evade enumeration, either by hiding or deflecting. The Post Enumeration Survey (PES), conducted after every Census since 1951, estimates these errors. The 2011 PES found a net omission rate of 2.3%, with the Eastern zone—bordering Bangladesh—showing the best coverage.

Nationally, the most frequently missed groups are infants and young, mobile adults in their twenties. However, in Eastern and Northeastern states, coverage is both better overall and more consistent across age groups, with no spike among young adults.

  • Net omission rate in 2011: 2.3% (23 persons per 1,000)
  • Eastern zone: Best coverage among all regions
  • Central and Northern zones: Account for 66% of the undercount (19 million out of 27.7 million)

Birthplace Misreporting and Migrant Stock Trends

Misreporting birthplace as India rather than Bangladesh introduces measurement error but does not hide the individual from the Census count. If large numbers of undocumented migrants did this, it would inflate the Muslim population growth rate in border districts beyond what fertility and natural increase explain. However, data shows no such inflation.

The migrant stock in India has seen a decline in those born in Bangladesh and Pakistan, with increases from Nepal. Despite this, about half of India’s migrant stock remains Bangladesh-born. In the last three Censuses, roughly 94% of Bangladesh-born residents lived in the five border states (West Bengal, Assam, Tripura, Meghalaya, and Mizoram).

  • Bangladesh-born population in India: Fell from ~4.0 million to 2.7 million
  • Share in border states: 94%, with minimal change over time
  • Age trend: Older migrants from Partition (1947) and Bangladesh Liberation War (1971) are ageing out

The evidence from official data suggests no surge of undocumented migrants from Bangladesh between 1991 and 2011. While the Census cannot confirm the absence of undocumented migrants, it does indicate that the scale claimed—20 million—is not supported by the data.