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_66549 ( "Manufacturer" text, "Transmission" text, "Engine Capacity" real, "Fuel Type" text, "L/100km Urban (Cold)" real, "L/100km Extra-Urban" real, "L/100km Combined" real, "mpg-UK Urban (Cold)" real, "mpg-UK Extra-Urban" real, "mpg-UK Combined" real, "mpg-US Urban" real, "mpg-US Extra-Urban" real, "mpg-US Combined" real, "CO 2 g/km" real, "Green Rating" text )

### Question ###
What's the CO2 g/km of a Fiat running on diesel with the L/100km urban more than 6.3 and an mpg-UK combined of 43.5?

### Accurate SQL ###

SELECT COUNT("CO 2 g/km") FROM table_66549 WHERE "Fuel Type" = 'diesel' AND "Manufacturer" = 'fiat' AND "L/100km Urban (Cold)" > '6.3' AND "mpg-UK Combined" = '43.5'