The problem is solved now. Thanks to a comment suggesting [this link](https://www.mobilereset99.com/intex-mobile-recovery-mode/) (Use volume buttons to move and power button to select any option) 



> **Method 1**

>* Power off your Intex Mobile, by holding the power button.

>* Hold down the Volume Up + Power Button.

>* After that, Release both Buttons when you see Intex Logo or Android Logo appears.

>* Now you can see Android Recovery Mode.



> **Method 2**

>* Power off your Intex Mobile, by holding the power button.

 >* Hold down the Volume Down + Power Button.

 >* After that, Release both Buttons when you see Intex Logo or Android Logo appears.

>* Now you can see Android Recovery Mode.

 

> **Method 3**

>* Power off your Intex Mobile, by holding the power button.

>* Hold down the Volume Up + Home + Power Button.

>* After that, Release both Buttons when you see Android exclamation mark appears.

>* Now you can see Android Recovery Mode, if not (While holding down the Power button press and release Volume Up Button).


> **Method 4**

>* Power off your Intex Mobile, by holding the power button.

>* Hold down the Volume Up + Power Button.

>* After that, Release both Buttons when you see Android exclamation mark appears.

> * Next, While holding down the Power button press and release Volume Up Button.

>* Now you can see Android Recovery Mode.

I tried the 4th method in the link.
But since <kbd>volume up</kbd> + <kbd>power </kbd> was restarting the device normally, I held down the <kbd>power </kbd> and was pressing and releasing the <kbd>volume up </kbd>
 button.
The device didn't go in recovery mode but it rebooted and started working **without** the popup "unfortunately system UI has stopped".