China has kicked off a once-a-decade census, a whirlwind 10-day head count that sees six million census takers scrutinise apartment blocks, scour migrant areas and scan rural villages to document massive demographic changes in the world’s most populous country.

And they aim to count every person.

The 2000 tally put China’s official population at 1.295 billion people, but missed migrant workers living in cities for less than six months. In the 10 years since, there has been an extensive shift in the population base as tens of millions of migrant workers have poured into urban areas looking for work.

Zhang Xueyuan, director of publicity for the Beijing census committee, said on Monday: “Wherever you are living from November 1 to 10, you will be counted.”

It is the sixth time China has carried out a national census.