The three fuel retailers had earlier stated that Air India owed Rs 5,000 crore in unpaid fuel bills.

Issuing an ultimatum to Air India, PSU oil majors on Thursday asked it to make the monthly lump sum payment by October 18 or they will stop the fuel supply at six major airports, according to an official document.

In a letter sent to Air India, the three oil PSUs -- Indian Oil Corporation Ltd (IOCL), Bharat Petroleum Corp Ltd (BPCL) and Hindustan Petroleum Corp Ltd (HPCL) -- said "the outstanding has not come down considerably in the absence of the committed monthly lump sum payment".

PTI has accessed the communique sent by the oil companies to the national carrier.

The three fuel retailers had earlier stated that Air India owed Rs 5,000 crore in unpaid fuel bills with payments being delayed by almost eight months.

On August 22, Indian Oil Corp, Bharat Petroleum Corp Ltd (BPCL) and Hindustan Petroleum Corp Ltd (HPCL) had stopped fuel supplies to Air India at six airports of Kochi, Mohali, Pune, Patna, Ranchi and Vizag over payment defaults.

However, after the intervention of the Ministry of Civil Aviation, they resumed the fuel supply on September 7.