Welcome to the site !!
From what i have researched it should get around 65kmpl , which would be somewhat within the range you are experiencing , how many miles (km) are on the bike now ?? ( i am assuming you bought the bike new ??), you mentioned Service , what was done at the service ?? (I am assuming it was done at a dealership ??) , has the type of fuel you are using changed to a lesser grade ?? (lower octane rating) , it is possible that its in need of a tune-up , and it could also be due to a traffic increase , where you might be at stops for longer periods , so it looks like you are not driving any farther distance , but the wait time sitting at a intersection , or in heavy traffic may be the issue , as the bike will still burn fuel while sitting idling , so a simple increase in traffic conditions could be the only cause for the perceived decrease in mileage , since the amount of distance your driving is not increasing , but the time the engine is running sitting in traffic is ,,, understand ??
Not sure if that helped any , as more info is needed from you as to the details of your riding conditions , when the bike was new to now , the more detailed info you give as to your riding conditions , and the time it took to travel a given distance when you first bought the bike , and the time it may take now , if the time has increased but the distance has not , that will be your answer , the more detailed your explanation of riding conditions , and service information , the easier it is for someone to give suggestions as to where to look for hopeful answers ......................