Racism against NE people

So, I am a punjabi from delhi, born and raised here and I recently attended the ed sheeran concert. As I was waiting in line a guy with east asian features walked by (who I assume was north east Indian), a group beside me started making incomprehensible chinese noises to themselves and laughing calling each other racists while doing so, thankfully they weren’t loud enough for the guy to hear them and he walked past. Although I know racism like this is widespread all over India but I have not seen many people confront them and I just wanted to know is this common for NE people to experience and if it is do you guys ever confront them about it?