How to get Best average from my Car

Dear Sir

I own a Maruti Wagon-R 2004 model, recently despite regular service/ throttle body clean/injector clean, my car still fails to clear Pollution Test.
Kindly suggest what needs to be done for this and eventually get good average from my car
My car gives me an average of 9kmpl these days, it use to give 14kmpl earlier
i know it’s old but still my first car. it has already done 2,40,000 kms till date and still running perfectly
please advise

The block piston assembly of your car needs to be refurbished or replaced in order to get back the original tolerances. If you do this, your power as well as mileage will return. It will meet emissions test too.