poor fuel economy

I have purchased a figo from kairali ford, cochin. its diesel Exi red with reg no: KL-7-BN-1226. overall performance is good and the vehicle is really rigid. But mileage seems to be pathetic. I am only getting 10 KM/litre in city whereas company is offering 15-16 KM/litre in city rides and above 20 in highways. My friend is also having the same mileage problem. Other than the poor fuel economy, the car seems to be very good and value for money. I dont know how an engine giving excellent mileage in fiesta and ikon is performing so badly in their own other car