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भारत सरकार · Government of India · Ministry of Statistics and Programme Implementation
FareSankhyaAirfare Price Index
Documentation

Methodology

How a quoted airfare becomes an official statistic, from basket definition to published index.

  1. 01
    Basket definition
  2. 02
    Scheduled scraping
  3. 03
    Cleaning
  4. 04
    Index engine
  5. 05
    Validation
  6. 06
    Publication

1. The basket

The index covers a fixed set of trunk city-pairs selected on DGCA domestic passenger volume. Each pair is priced in both directions, economy cabin, one adult, no ancillaries.

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2. Collection

Fares are read from five airline websites and six online travel agents at fixed booking windows of D-7, D-15 and D-30, sampled four times daily at 06:00, 12:00, 18:00 and 21:00 IST. Self-healing scrapers detect layout changes and fall back to the site's own fare API where one is exposed.

A monthly survey observes a price once. APIx observes each route roughly 30 times a month per booking window, which is what allows the index to register intraday volatility that the current CPI collection cannot.

3. Normalisation

Every quote is reduced to a comparable all-in price: base fare plus statutory taxes and user development fees, excluding seat selection, baggage add-ons and convenience fees. Fare classes are mapped to a common economy definition, and airline-quoted prices are cross-checked against OTA quotes for the same flight number to catch error fares.

4. Index formula

At the elementary level, where no expenditure weights exist within a route, the unweighted geometric mean of price relatives (Jevons) is used:

IJ = ∏ ( pt,i / p0,i )1/n

Route sub-indices are then aggregated with a Modified Laspeyres using passenger-traffic weights held fixed for the reference year:

APIxt = Σ wi · ( IJ,i,t / IJ,i,0 ) × 100

Weights are reviewed annually against DGCA traffic data. The reference base is January 2024 = 100.

5. Publication & revision

Daily and weekly series are published as experimental statistics. The monthly series is the input to CPI Transport & Communication and is final on release; corrections, if any, are footnoted and carried in the next monthly bulletin rather than applied silently.