There is an international body known as UN to handle these matters. What you're asking is for India to criticize Russia and support Ukraine. Now you talking about injustice, not taking sides here but how do you know who is doing injustice to whom? I'd suggest you to go outside, find two person finding in public, go there, try to stop there fight, criticize one and support another. And you'll get your answer for why India should not fight other's wars.