I'm being paid 50% of colleague for the same role.

I joined a startup in 2021 with a 6 LPA package. After about a year I learnt that one of my colleague, who had joined 3 month before me, and who's from the same batch (2021) as mine is being paid 12 LPA for the same role, even though I'm much better than him in terms of programming knowledge and development skills. Learning that killed all the motivation I had to work and now I feel cheated and deceived. How should I deal with this situation ?