Indian simcard not working on my iphone 5sfrom uk

please go through this: https://support.apple.com/en-us/HT201415

• device might be locked to use only with specific wireless carrier

in that case have a look at this: https://support.apple.com/en-us/HT201328

You could have two problems:

Your device is locked to a different (UK) carrier. Should be this case, only the previous carrier can unlock that device for you. See this support guide: How to unlock your iPhone for use with a different carrier - Apple Support

or

You've tried to use an Indian carrier's SIM card not supported by Apple. Check this list:

Wireless carrier support and features for iPhone in Asia-Pacific - Apple Support

Regards

Giulio