The Indian government has done what authorities in most market economies would rarely dare to try — it has forced Indian carriers to slash domestic airfares by as much as a quarter, and to publish fare ranges on every route on their websites regardless of travel dates. While helping consumers is admirable, is New Delhi crossing a line?

Angered by the pricing policies of India’s airlines, including low-cost carriers IndiGo, SpiceJet and GoAir, the Directorate General of Civil Aviation (DGCA) gave them an ultimatum last weekend to lower fares or face severe consequences, the Indian press reported. Within hours, fares dropped between 20 and 25 percent…