Hello Vibhore_0,
We, just users like you, cannot diagnose that kind of issue remotely, sorry.
If you're sure that nothing (cover/case/screen protector/dirt) is interfering with your touch screen, it might be a hardware (screen? digitizer? other internal component?) failure, and I suggest that you contact Apple Support directly, using this link:--> Contact - Official Apple Support , or, even better, make an appointment (*) and have your device inspected at an Apple Store or AASP (Apple Authorized Service Provider) among this list:--> https://locate.apple.com/choose-country-region . After checking it out, they'll give you all the available options.
Regards
Giulio
(*) You can do it: