1. The problem asks for the maximum number of people who live in Birmingham given that the population is rounded to the nearest 1000 as 1 020 000. 2. When rounding to the nearest 1000, numbers from $1{,}019{,}500$ up to $1{,}020{,}499$ round to $1{,}020{,}000$. 3. To find the maximum number of people, we take the upper limit just before rounding up to the next 1000, that is one less than $1{,}020{,}500$. 4. Hence, the maximum number is $1{,}020{,}499$. 5. Among the options, $1{,}020{,}499$ matches the maximum number of people who could live in Birmingham.