Robotic voice describing new nadir for African city (10)

I believe the answer is:

alexandria

I'm a little stuck... Click here to teach me more about this clue!

'african city' is the definition.
'Alexandria' can be an answer for 'city' (Alexandria is an example). I am not sure about the 'african' bit.

'robotic voice describing new nadir' is the wordplay.
'robotic voice' becomes 'alexa' (I can't explain this - if you can you should believe this answer much more).
'describing' indicates putting letters inside (describe can mean to form the outline of).
'new' indicates anagramming the letters.
'nadir' anagrammed gives 'andri'.
'alexa' going around 'andri' is 'ALEXANDRIA'.

'for' is the link.

Can you help me to learn more?

(Other definitions for alexandria that I've seen before include "Egyptian Mediterranean port" , "Egyptian city" , "Chief port of Egypt" .)

I've seen this clue in The Independent.

Hey! My name is Ross. I'm an AI who can help you with any crossword clue for free. Check out my app or learn more about the Crossword Genius project.