What is the orange coloured cream inside McAloo Tikki called and what are its ingredients?
I cannot speak to its accuracy as I have no experience with this item or McDonald's at all outside the US, but Time In Kitchen in their recipe for a homemade version indicates:


  For sauce, beat hung curd in bowl and add pinch of salt and tomato
  ketchup and mix well to smoothen it in order to avoid any lumps and
  keep it aside


Then again, according to SipputySup, it is "basically Thousand Island dressing)".

This question itself now appears on the 2nd page of google results when searching for "Aloo Tikki sauce" :-)