Update regarding taking transit flight to China
2021/02/18

With the COVID-19 pandemic still rampant globally and the risk of cross-infection remaining high in international travels, it is highly recommended that you do not travel unless for essential purposes.

From 1 March 2021, if you are travelling from Ireland to China for essential purposes, please make no more than one transit. Please upload your itinerary and your Irish residence permit (or visa) when applying for the Health Code or Health Declaration Certificate (HDC) Code. You may risk being denied a green Health Code or HDC Code if your itinerary does not meet the above requirements.

EMBASSY OF THE PEOPLE'S REPUBLIC OF CHINA IN IRELAND ALL RIGHTS RESERVED
http://ie.china-embassy.org