و عليكم السلام 1- I think (The city is on fire ) it give the meaning of المدينة يشتعل أجوائها like the city has problems that make it not rest, and sometimes fire = ضرب النار shoot with gun The city is in flames>> I think it means in this case المدينة تحترق and I think the whole sentence will indicate the meaning for you in both cases. 2-The fish is IN THE fire السمكة في النار as a cook way.