The Competition Commission of India (CCI) has found no evidence that the country’s biggest airline, IndiGo, and four rival carriers colluded to fix ticket prices, three sources with direct knowledge of the matter said.

In 2015, the CCI had ordered a probe into allegations of anti-competitive practices after similar fares were being offered on certain routes by IndiGo, SpiceJet, GoAir, state-run Air India and the now defunct Jet Airways.

The CCI inquiry, which included an analysis of the algorithms airlines use to determine ticket fares, found that all five airlines were working independently, the three sources said.

“No direct evidence of cartelisation was found,” said one of the sources, who added the investigation also did not reveal any communication among the airline executives to fix prices.

Budget airline IndiGo said in a statement “the case is without merit” and added that it has been co-operating with the investigation.

SpiceJet, GoAir, Air India and Jet Airways did not respond to requests for comment. The CCI did not respond to questions.

An adverse finding could have led to a fine of up to three times the profit made in each year the prices were fixed, or 10 per cent of the annual revenue, whichever is higher. Domestic airlines are already grappling with slow growth in air traffic.

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