IndiGo, Air India, and others refuse to share data on airfares in a brewing tiff with policymakers

India’s airlines have refused to share data on airfares sought by the government regulator, setting up a clash with policymakers who are trying to improve protections for consumers in a market that is a near-duopoly.

Market leaders IndiGo and Air India Group, along with SpiceJet, told the aviation regulator they can’t share the data as disclosing the information would lead to commercial setbacks, according to a March 11 letter by the Federation of Indian Airlines that was seen by…