Below is the list of tables from the database along with their columns and datatype. Need to generate an accurate SQL query for the question.
Only use the columns present in the respective table. Only use the columns which are required to generate the SQL query. Only use table joins if required and not otherwise.

### Tables ###
TABLE: CREATE TABLE table_2866503_1 (us_air_date VARCHAR, us_viewers__million_ VARCHAR)

### Question ###
What is the U.S. air date when the U.S. viewers are 7.5 million?

### Accurate SQL ###

SELECT us_air_date FROM table_2866503_1 WHERE us_viewers__million_ = "7.5"