Change Oil, Oil Filter, Air Filter, Get Throttle Body and Converter cleaned. Maybe get it computer checked too. When was the last time you changed those things? has your car ever given you a 13-14 average? how long ago was it. What brand tyres and tyre size do you have?
My City 2010 does 14.2 kmpl within city with AC on and 15.5 kmpl without AC.