I found this
column useful, it says the backlog of citizenship applications is about 468,000 now (October 27, 2021), increased by 98,000 from 370,000 (July 6, 2021)
The author defines the backlog as the total processing inventory, I assume these are not only applicants who has been waiting since 2019 but also applicants who received AOR, BG checks, test invites etc. in 2020-21
The following is my attempt to better understand if IRCC is capable to deal with the backlog. I'm waiting for my Oath Ceremony since July. And I hope my calculations will help someone be less stressful about it. I made these rough assumptions but I don't pretend I know the truth (so please don't judge =))
Assumptions:
Backlog = 468,000 (people are waiting on different stages but eventually they all will end up with the Oath ceremony)
For Oath ceremonies, there are 14 citizenship judges in Canada (maybe more, LinkedIn shows 18 citizenship judges working for IRCC)
An online Oath ceremony usually accommodates about 20 people (IRCC can also change the number of people per session)
It contributes to the 1,300 - 1,671 sessions per judge. If they organize 4 sessions per day (1-hour sessions + breaks), then they need 325 - 414 days to process the backlog before new applicants will create another backlog in 2022
Perhaps, the reality is even more complex but I think IRCC hired more judges or increased the capacity per session to process the backlog faster, e.g. in one year
I hope it helps