How many clients who live in New York City submitted their complaints via fax?
submitted complaints via fax refers to "Submitted via" = 'Fax';
SELECT COUNT(T1.client_id) FROM client AS T1 INNER JOIN events AS T2 ON T1.client_id = T2.Client_ID WHERE T1.city = 'New York City' AND T2.`Submitted via` = 'Fax'