The Xiaomi Mi 5S is the first phone to come with a non-porous ultrasonic fingerprint scanner that lives under the 2.5 D front glass panel and since it features a full metalunibody design, there is no room for a removable battery.
All these other brands under 30K had copied Iphone design even upto 99 % with special features such as finger print sensor and metalunibody design phones at such cheap rates.