However, school closures between December 2020 and March 2021 due to the coronavirus (COVID-19) pandemic meant that the census date was delayed to 20 April 2021.
Fodd bynnag, roedd ysgolion ar gau rhwng Rhagfyr 2020 a Mawrth 2021 oherwydd pandemig y coronafeirws (COVID-19) ac felly gohiriwyd dyddiad y cyfrifiad i 20 Ebrill 2021.