Unfortunately, there are not many diesels with automatic transmission in the price range you are looking at. But for your kind of driving (bumper-to-bumper traffic), we suggest you go in for the Hyundai Getz. It is small enough to negotiate traffic, but has enough room inside to keep you happy when you are really stuck. And don't worry, though it comes with a manual gearbox, it is quite easy to drive. Alternatively, you can look at the Hyundai Santro AT (automatic) which we think does not offer value for money