Inflation — CPI & WPI

WPI tracks prices at the wholesale, or producer, level — what a factory or a wholesaler charges before goods reach a retail shelf — and it excludes services entirely, covering only manufactured products, primary articles and fuel & power. It's a fundamentally different basket from CPI, measured at a different stage of the supply chain, which is why the two indices can and often do print different inflation numbers in the same month. India's monetary policy targets CPI, not WPI, precisely because CPI reflects what a household actually experiences at checkout, while WPI is more useful for tracking cost pressure building up in the pipeline before it reaches consumers — or for gauging producer margins directly.

Core inflation is CPI with the most volatile components — food and fuel — stripped out, leaving the more slow-moving, demand-driven prices of things like housing, healthcare, education and services. Food prices swing on a bad monsoon or a diesel price spike in ways that have nothing to do with overall demand in the economy; fuel prices swing on global crude markets. Strip both out, and what remains tells a central bank whether inflation pressure is "sticky" — embedded in wage and demand dynamics that monetary policy can actually influence — rather than a one-off supply shock that will fade on its own once the harvest normalises or crude prices ease.

The GDP Deflator is the broadest inflation measure of all: it's simply Nominal GDP divided by Real GDP, expressed as an index. Because it's derived from the entire economy's output rather than a fixed household basket, it captures price changes in things CPI never touches — capital goods, government spending, exports and imports. For FY25-26, Nominal GDP of ₹357.14 lakh crore against Real GDP of ₹322.58 lakh crore implies a deflator of roughly 110.7, or an economy-wide price rise near 10.7% — visibly higher than the same year's CPI print, precisely because it's counting price changes across a far wider slice of the economy than what sits in a household's shopping basket.

Deflation is the mirror image of inflation — the general price level actually falling, not merely rising more slowly. It's rare and unwelcome: falling prices make consumers delay purchases expecting still-lower prices tomorrow, which chokes demand and can spiral into a genuine slowdown, a dynamic Japan has wrestled with for decades. A low print like January 2026's 2.75% CPI is disinflation — inflation slowing down — not deflation; prices are still rising, just more gently. Stagflation is a different, and in some ways scarier, combination: high inflation arriving together with weak growth and rising unemployment, which leaves a central bank with no clean tool, since raising rates to fight inflation would deepen the growth slump, and cutting rates to support growth would fuel more inflation. India hasn't experienced textbook stagflation, but its closest brush came around 2012-13, when growth slowed toward the 5% mark even as retail inflation ran close to double digits.