Even so, in India, we have opted for WPI over CPI as a second best choice for a number of reasons. First and most importantly, we do not have a single CPI that is representative of the whole country. Until recently we had four, and of those, currently we have three CPIs representing different segments of the population.
While WPI is computed on an all-India basis, CPIs are constructed for specific centres and then aggregated to an all-India index. Second, WPI is available with a slightly shorter lag than the CPIs. Third, WPI has a broader coverage than the CPIs in terms of the number of commodities, number of quotations, inclusion of non-agricultural products and tradeable items.