Born to Algerian parents, she grew up in poor conditions in Tourcoing as the ninth child in the family of 13.

In 2016, she was made vice-chair of the Volkswagen emissions scandal inquiry into whether the EU should have acted more quickly to address the issue.

In addition to her committee assignments, Delli has been a member of the parliament's delegations for relations with India (2009-2019) and China (since 2019).

[5] In a letter to President of the European Parliament David Sassoli in late 2019, Delli and Ismail Ertug asked the Parliament to sanction Angel Dzhambazki on the grounds he made xenophobic remarks about them and thereby breached the legislature's code of conduct.

[7] When supporting the ZAD (Zone to Defend) against a motorway near Strasbourg in 2018, Delli was sprayed in the face and mouth with tear gas by the police.