When crude oil prices surge 13% overnight in a single session, as they did Friday after Israel's strikes on Iran, India's fossil fuel sector reveals its fundamental divide: those who dig/drill it up versus those who process it.The upstream fossil fuel producers celebrated. Oil and Natural Gas Corporation closed Friday up 1.28%, making it the second largest gainer in the Nifty-50 index after defence stock BEL, while Oil India gained 2.17% on the same commodity tailwinds.