What is STT tax? Why just a 0.03% hike news spooked investors and caused a market bloodbath?

What is STT Tax? Budget 2026 has sparked widespread investor anxiety by hiking the STT on futures to 0.05% and options to 0.15%. Investors are worried that these "friction costs" will kill market liquidity and erase profits for retail traders, effectively signaling a government crackdown on speculative F&O activity.