You might not even need India to go Hindu nationalist long term. Just have the more extreme factions within the Hindutva movement adopt the Swastika as their symbol and then commit massacres and violent ethnic clensing of Muslims in Hindu majority areas during India's partition under the Swastika banner. Nehru cracked down pretty hard on them after one of their fanatical members tried to kill Gandhi for stating "Yes, I am a Muslim and a Hindu and a Christian and a Jew and so are all of you."
It was Gandhi's concilliatory influence, which helped prevent the worst. Imagine if the assassin had been successful and had managed, as he originally intended, to blame the Muslims for the bomb attack, that would've killed Gandhi. And later on anti-muslim terrorist groups in the West might adopt the Swastika banner as a symbol of their struggle against Muslim minorities in their countries, with the symbol appearing on mosques, after having fallen victim to far-right arsonist attacks.