India began a yearlong effort to count the world’s (presumably) largest population.

A 2011 headcount recorded 1.21 billion. COVID-19 delayed the 2021 edition, but estimates now place the figure at 1.47 billion. That probably isn’t too far off the mark, but any errors could starkly affect parliamentary seat allocations if redrawn. Those changes will likely be greater this time, given the 15-year gap and the move to a digital census system; only about half of Indians have access to smartphones, requiring a huge logistical effort in which three million people will be enlisted in the count.

This census is also particularly controversial, including questions on respondents’ caste for the first time in nearly a century.