I suggest to use
ranking functions[
^].
For example:
SELECT RowNo, [Name], Sal
FROM (
SELECT ROW_NUMBER() OVER(PARTITION BY City ORDER BY Sal DESC) AS RowNo, [Name], Sal
FROM Employee
WHERE City IN ('DEL','MUM')
) AS T
WHERE RowNo IN (1,2)
NOTE: Depending on your needs, you should use proper ranking function.