Notwithstanding the long-run lead-lag relationship, the divergence between WPI and CPI has accentuated since early 2008 (Chart 2). Chart 2 Divergence between WPI and CPI Inflation  BIS Review 5/2010  3  12. This could be attributed to the following factors. First, the price of minerals and metals went up sharply during May–June 2008 and then fell precipitously reflecting global trends.
Since metals and alloys do not form a part of the CPI group, this accentuated the divergence between CPI and WPI. Second, there was a similar trend as metals in crude prices which had a larger influence on WPI than CPI.