New Delhi, May 15 -- Although retail prices stayed largely cool, inflation at the wholesale level ran hot last month in a sign that supply shortages caused by the war in West Asia have started to feed price pressures.

The wholesale inflation rate for April more than doubled to 8.3% from a year earlier, compared to 3.9% in March, according to government data issued on Thursday.

April's reading was the highest in three-and-a-half years. Prices of crude petroleum and natural gas were up 67.2% from a year earlier, while the fuel and power inflation rate surged to 24.7% in April from almost 1.1% in March. Manufactured products also saw their inflation rise to 4.6% from 3.4%.

On the whole, it is clear that higher input costs are driving up f...