My Budget Is 16000
Camera 13,5 upgradeable to android M, 2 Gb or 3 GB of ram, octa core processor , good battery life ,soft keys as well as physical keys
There is only one phone which comes with software and physical keys that is OnePlus One 64GB but its out of your budget. within your budget the best option with your requirements is eaisly the Moto G 3rd Gen comes with 2GB ram and a great processor octa and quad core mean nothing it depends on how good the chipset is phones perform better on good quad core compared to octa cores in this price range. it also has one of the best cameras in this price range since it uses the same camera hardware as the much costlier nexus 6. it will be one of the first non nexus devices to get Android M since motorola uses stock android and updates the fastest. it has best in class battery life too which beats almost all flagship devices in battery life.