India's central bank on Tuesday raised its lending rates by a bigger-than-expected 50 basis points, its ninth hike in 15 months in a bid to curb stubborn inflation in the country's booming economy. The Reserve Bank of India raised its repo -- the rate at which it lends to commercial banks -- to 7.25 percent and increased its reverse repo -- the rate it pays to banks for deposits -- to 6.25 per cent.