** Shares of Indian refiners drop amid a 0.8% dip in benchmark Nifty 50 index .NSEI after U.S. announced additional 25% tariff on Indian goods over its Russian oil purchases .BO
** Hindustan Petroleum Corp HPCL.NS, Bharat Petroleum BPCL.NS drop 1.9% and 2.5%, respectively
** Heavyweight Reliance Industries RELI.NS declines 1.6%; co flags that continuing geopolitical and tariff-related uncertainties may affect trade flows and supply-demand balance
** Indian Oil Corp IOC.NS down 1.4%
** Sub-indexes Nifty oil and gas .NIFOILGAS and energy .NIFTYENR down 1.6% each
** Jefferies analysts say "a clean break from Russian trade on all items will be tough for India"
** Analysts flag fears over a spike in costs if India were to replace Russian crude oil with other sources