The SpiceJet move was copied soon by two other budget carriers - IndiGo and GoAir - as well with similar offers, said travel agents.
However, the airlines' officials were not available for confirmation.
Triggering a fresh bout of fare war, SpiceJet announced a 50 per cent rebate on base fares and fuel surcharge on all flights for travel 30 days ahead of booking.
"This kind of limited period off-season sale is a routine practice in the airline industry across the world and tactical inventory management, to help airlines fill seats that would otherwise go empty. It is revenue-positive for the airline," a SpiceJet spokesperson said.
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"IndiGo and GoAir too have come out with similar offers," a travel agent said.
The move is being seen as an attempt by carriers to mop up funds for the March quarter, which is traditionally a weak period both from demand and revenue points of view.
"SpiceJet and Indigo slashing airfares is an attempt to garner early bookings for the coming summer season," travel portal Yatra.Com president Sharat Dhall said.