New Delhi, October 15: The biggest public sector bank, State Bank of India (SBI) has shown a “serious concern” over the country’s deteriorating wholesale price index (WPI) core inflation, citing poor purchasing power. According to SBI Bank’s research arm, SBI Ecowrap, the WPI core inflation declined to 38-months low to minus 1.07 per cent in September 2019, from minus 0.49 per cent in August 2019.