NEW DELHI, Aug. 20 -- India's largest airline, IndiGo, strengthened its dominance of the domestic skies in July, raising its market share to a record 67.4%, while Akasa Air and SpiceJet lost ground.

Air India Group, the country's second-largest aviation company, was steady at around 24% of the market, according to the monthly passenger traffic data released by the Directorate General of Civil Aviation (DGCA).

Share of Akasa fell to 5.5% from 6.4% in June, while SpiceJet's declined to 1.6% from 1.9%.

Put simply, more than two out of every three domestic passengers flew IndiGo in July, while nearly one in four travelled on an Air India Group airline, which includes Air India and Air India Express. Together the two airlines control nearly...