According to the statistic collected by the Election Observation Project, as of 4 pm on July 11, 214 (55%) of the 389 pan-democratic District Councillors have left their posts. The reasons included arrest (27 people), disqualification (8 people), and resignation (208 people).
Continuous changes since the implementation of the National Security Law in July 2020 led to the arrests, detentions or convictions of the District Councillors. Some were disqualified, some resigned voluntarily, while others fled Hong Kong.
In May 2021, the Public Offices (Candidacy & Taking Up Offices) (Miscellaneous Amendments) Ordinance 2021 was gazetted and implemented, setting off another wave of about 30 district councillors leaving their posts before June.
A few days ago (July 6), some media quoted “government sources” that around 230 District Councillors would not meet the requirements of the oath, and even pointed out that these district councillors might repay their salaries and allowances, leading to an unprecedented wave of resignations by District Councillors.
The government has not clarified the relevant rumours, and the Secretary for Home Affairs Xu Yingwei has not responded to the resignation wave.
So far, the government believes that it will not arrange by-elections for the vacancy of district council seats on the grounds of the pandemic. However, it has actively followed Beijing’s instructions and arrangements to prepare for the Chief Executive Election Committee in September 2021, the Legislative Council election in December 2021, and the March 2022 Chief Executive Election.

List of District Councillors affected:

Hong Kong Island (EOP_DC 2019_2021 Status HKI)
New Territories East (EOP_DC 2019_2021 Status NTE)
New Territories West (EOP_DC 2019_2021 Status NTW)