It was known that in China, since the time of the one-child policy, many children « out of quota » have no legal and official existence. In Brazil too, for different reasons, nearly 3 million people, or 1.5% of the Brazilian population, are « off the radar ». Access to health care, education, and administrative services in general becomes a path fraught with obstacles, if not insurmountable.

https://brasil.elpais.com/brasil/2021-11-28/invisiveis-no-brasil-sem-documento-e-dignidade-eu-nem-no-mundo-existo.html

https://www.courrierinternational.com/article/identite-sans-papiers-sans-dignite-ces-bresiliens-invisibles-qui-nexistent-pas