Retail inflation, also known as Consumer Price Index (CPI) inflation, is the rate at which the prices of goods and services that consumers buy for personal use increase over time. It is a macroeconomic indicator based on the CPI that tracks the change in retail prices of goods and services which households purchase for daily consumption. The CPI monitors retail prices at a certain level for a particular commodity; price movement of goods and services at rural, urban and all-India levels. The change in the price index over a period of time is referred to as CPI-based inflation, or retail inflation. To measure inflation, we estimate how much CPI has increased in terms of percentage change over the same period the previous year. If prices have fallen, it is known as deflation (negative inflation). The Central Bank (RBI) pays very close attention to this figure in its role of maintaining price stability in the economy. The CPI is an important indicator of price stability in the economy, measuring the average change in prices over time of all goods and services purchased by all urban consumers.