NEW DELHI (AP) — India has begun the world’s largest national population count, which could reshape welfare programs and political representation across the country.

The previous census in 2011 recorded a population of 1.21 billion. It’s now estimated to be more than 1.4 billion, making India the most populous nation.

The new census had been planned for 2021 but was postponed due to the COVID-19 pandemic and logistical challenges.

Here’s how India’s census works and why it is significant: