Taliban soldiers who have delivered food to the plane say the smell inside is rancid, a sign that people have been sick.
But Singh said the aircraft's doors and rear chute were opened to air out the interior of the plane, which has been on the ground in Kandahar since Saturday.
Earlier, Indian civil aviation official Ravinder Gupta said Taliban guards had been given permission to open the pipes of the aircraft's toilets from the outside.
The plane's engines shut down early Tuesday, causing concern among Indian engineers who said that without power, there would be no air circulation. Also, without working engines, heat will no longer be available for the passengers as temperatures at night hover around freezing in Kandahar.
The Taliban said they were allowed to give the passengers food after as many as 26 hours without eating. They sent fruit and cooked lentils aboard, apparently out of respect for the many Indians on board, many of whom are likely Hindu and do not eat meat.
The International Red Cross has been sending medicines onto the aircraft for a doctor who is among the passengers, said Peter Iseli, a Red Cross representative at Kandahar Airport.
The passengers' ordeal began Friday afternoon in the skies over India during a routine flight from Katmandu to New Delhi. The hijackers came from the rear of the plane soon after the meal was served and threw plates of food in the aisles, newspapers quoted some of the 27 passengers freed during a stopover in the United Arab Emirates as saying.
The hijackers ordered people to tie pieces of cloth around their eyes so they couldn't see the hijackers, Indian papers quoted freed passengers as saying.
Rippan Katyal, one passenger who had been returning from his honeymoon, was knifed to death by the hijackers after yanking off his blindfold twice.
His bride, Rachna, is still on the plane. On Sunday, the hijackers refused a Taliban request to let her leave.
The plane was carrying 178 passengers and 11 crew members when it took off Friday. The passengers included 150 Indians, eight Nepalese, one Canadian, one American, four Swiss, four Spaniards, one Belgian, one Japanese, one Australian, two French and one Italian. Four passengers were not listed by nationality.
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