The city you live in has a population of over 100,000 and yet it isn’t found in the atlas. This happens sometimes. The atlas is culled by running a Python script on the Geonames.org Gazetteer downloadable data. When the script is run it checks for cities population 100 or more and includes it in the atlas. But here’s the thing: your city is missing not because of Geonames but your country’s census program. I was recently looking up a city that didn’t show up in the atlas but Google reported as having a population of over 100,000. Checking Geonames.org, where you can enter the name of the city and get a listing back it was indeed in their database but there was no population given. The population of the administrative district (like a county in the US) was shown as over 1 million. But the atlas does not contain administrative districts or the atlas would be too large to include.
So what to do? That’s where the Map feature of JyotishTools, Tropical Skies and JyotishTools Pro comes in. You can look for the city there and once selected it will return the coordinates of that city. It does not however return the time zone. To solve that just find a nearby city in that country and use that time zone. Places like India (where the missing city above was located) only have one time zone and it does not observe Daylight Saving Time.
So why don’t I just add the missing city? Way too much work and probably way too many locations with the same problem. Get your politicians to fix the problem instead and include such cities in the census. BTW, it’s been estimated by other astrologers concerned about atlas accuracy that it would probably require a very large staff to keep up on changes and maintain such an atlas. Geonames.org does a good job as is and even contains the time zone codes for the IANA time zone database which is historical in nature (knows if a date was DST or not).