BLR comes from Bangalore and COK from Cochin, because IATA three-letter codes were assigned decades ago and stay fixed even when a city is renamed. Changing a code would ripple through tickets, timetables and baggage systems worldwide. Airports also carry a four-letter ICAO code, used by air traffic control rather than on your ticket.
Updated July 2026 · HappyFares
Every Indian traveller eventually notices it. The city changed its name years ago, but the boarding pass still says BOM, CCU or MAA. There is a reason, and it is more practical than sentimental.
What is the difference between an IATA code and an ICAO code?
They serve two different industries. The three-letter IATA code is the commercial one: it appears on your ticket, your baggage tag, the departure board and every booking site. The four-letter ICAO code is the operational one, used in flight plans, air traffic control messages and aviation weather reports, and you will almost never see it as a passenger.
ICAO codes are geographic. India sits in the V block, with the second letter grouped roughly by region: VI for the north, VA for the west, VE for the east and VO for the south. That is why Delhi is VIDP while Mumbai is VABB, even though their IATA codes look unrelated.
| City | IATA | ICAO |
|---|---|---|
| Delhi | DEL | VIDP |
| Mumbai | BOM | VABB |
| Bengaluru | BLR | VOBL |
| Chennai | MAA | VOMM |
| Kolkata | CCU | VECC |
| Kochi | COK | VOCI |
Why is Bengaluru BLR and Chennai MAA?
Because the codes were handed out when those cities were called Bangalore, Madras, Bombay and Calcutta. BLR, MAA, BOM and CCU are simply frozen snapshots of an earlier map. Thiruvananthapuram is TRV from Trivandrum, Kochi is COK from Cochin, and Pune is PNQ from Poona for the same reason.
Chennai’s MAA is the one people find hardest to decode. It is generally traced back to Madras, with the airport at Meenambakkam, and the ICAO code VOMM preserves the same history in a different form.
The codes survive because they are load-bearing. A three-letter identifier sits inside reservation systems, fare filings, baggage sorting, timetables, cargo manifests and decades of historic records. Renaming Chennai’s airport to Chennai International changed the name on the terminal. Changing MAA would have meant changing every system that has ever referenced it, worldwide, at once.
Why do so many Indian airports start with IX?
Look at a domestic route map and the pattern jumps out: IXC Chandigarh, IXB Bagdogra, IXE Mangaluru, IXR Ranchi, IXM Madurai, IXJ Jammu, IXL Leh, IXZ Port Blair, IXA Agartala, IXU Aurangabad. Dozens of Indian airports share that prefix.
The usual explanation is straightforward supply. The obvious three-letter combinations for many Indian city names were already taken elsewhere in the world by the time these airports were coded, so India was allocated a block of identifiers beginning with IX. It is administrative housekeeping rather than a code with hidden meaning.
The practical effect is that these codes tell you nothing about the city. IXE does not sound like Mangaluru and IXZ does not sound like Port Blair, so on smaller regional routes it is worth reading the airport name on the ticket rather than trusting the letters to look familiar.
Does booking the wrong code actually cause problems?
It does, and it is an expensive mistake because a wrong-airport booking is usually treated as a change or a fresh ticket rather than an error to be fixed for free. Three situations cause most of the trouble.
The first is one city with two airports. Goa is the clearest Indian example: GOI is Dabolim in the south and GOX is the newer Manohar International Airport at Mopa in the north, and they are a long drive apart. The Delhi and Mumbai regions are adding new airports of their own, each of which gets its own code, so this list is growing rather than shrinking.
The second is codes that look alike or sound alike. Kerala alone has COK for Kochi, CCJ for Kozhikode and CNN for Kannur, and picking the wrong one on a dropdown is easier than it sounds. The third is city codes, which some metropolitan areas use to cover all their airports in a single search, so a result can quietly resolve to whichever airport the system chose.
- Read the three-letter code on the itinerary, not just the city name
- Check the airport name printed underneath it before you pay
- For connections, confirm both flights use the same airport code, or budget real time for the transfer
- At check-in, glance at the code on your baggage tag before the bag goes down the belt
Who assigns airport codes, and do new ones still appear?
IATA assigns and publishes the three-letter location identifiers used commercially, while ICAO location indicators are allocated within each country’s block in coordination with the national authority. In India that means the codes sit alongside the airport licensing and operational framework overseen by DGCA and the Airports Authority of India.
New codes do appear, because new airports keep opening. Goa’s second airport arriving as GOX is a recent example, and the major new airports serving the Delhi and Mumbai regions each get their own identifier as they come into service. Existing codes, on the other hand, almost never change. When Hyderabad’s commercial operations moved from Begumpet to the new airport at Shamshabad, the HYD code moved with the traffic rather than being retired.
Common Questions
Why is Mumbai BOM?
Because the code dates from when the city was Bombay. The airport has since been renamed Chhatrapati Shivaji Maharaj International Airport and the city became Mumbai, but the IATA code stayed BOM and the ICAO code remains VABB. Both changes would have meant rewriting global systems for no operational gain.
Do airport codes ever change?
Rarely, and only with good reason, because a change has to propagate through every reservation, baggage and scheduling system that uses it. Codes are far more likely to move than to disappear, as happened when Hyderabad’s traffic shifted to a new airport and kept HYD.
What is the code printed on my baggage tag?
It is the three-letter IATA code of the airport where your bag is meant to end up, alongside the airline and flight details. Checking it takes two seconds at the counter and is the single easiest way to catch a mis-tagged bag before it travels somewhere you are not going.
Is COK anywhere near Kochi city?
Not especially. Cochin International Airport is at Nedumbassery, well outside the city, so allow real travel time in both directions. This is common in India, where several major airports sit a long way from the centre of the city whose name they carry.
What do 6E and AI mean on my ticket?
They are two-letter IATA airline designators, 6E for IndiGo and AI for Air India. Airlines also hold a three-letter ICAO designator used in flight plans, plus a separate radio callsign that controllers use on frequency, which is why the voice on the radio may not match the code on your boarding pass.
Why do some codes look nothing like the city name?
Usually one of three reasons: the code follows the city’s older name, it follows the name of the locality where the airport sits rather than the city, or it came out of a block allocation like the IX series. None of them are meant to be guessable, which is why the airport name on the ticket matters more than the letters.
Know your codes? Compare fares across airlines on HappyFares and double-check the airport code on your itinerary before you book.
Airport details, codes for new airports and operating terminals change. Verify current specifics with your airline, DGCA or the airport before you travel.
