Good News! 
.I would say the first step that we did was to give ad in the weekly local newspaper. (For instance, Annanagar times, which is the weekly newspaper that comes out on Sunday every week). We placed an ad for a Missing Dog with a picture of my dog. We got several calls from people who read the newspaper about seeing our dog at different places of the city. Reason being people travel a lot and the chances of them spotting a dog are high. I would also suggest “giving ad in the weekly newspaper of the surrounding areas”.
The next major thing that we did was to post in Facebook and other public forums. There are few groups like “The Pound”, “Chennai Adoption Drive” in Facebook. They post on these pages about missing dogs and dogs that have been spotted in certain areas. We could post on such pages and also look through these pages to see if someone has posted on these pages pertaining to our dog. These 2 steps together helped us to find our dog. Our dog’s picture was posted by a person in one of these groups and people had linked me to the page to see if it was my dog. It indeed was mine. So through that person we found the area where my dog was in and we found him.
Plus our dog knows our “CAR HORN” sound very well. So we honked in the street where the dog was last seen and it came running from wherever it was. So I would suggest if the dog is used to things like car honks from your house, try doing those as they recognize them.
Also, we spent hours together searching for it and without finding it. It was a lot of work but we kept looking for it and found it.”
