as.Date function giving incorrect year [duplicate]

Here is the solution + explanation:

> # %Y is used for 4 digit numbers
> 
> as.Date('28/3/2021', '%d/%m/%Y')
[1] "2021-03-28"
> 
> # while %y for 2 digits
> 
> as.Date('28/3/21', '%d/%m/%y')
[1] "2021-03-28"
>