Another doctor at the site, Prem Pokhriyal, said the men had been asked to avoid heavy workouts that could boost the accumulation of carbon dioxide gas in the confined space as they breathe out.
The trapped men are low-wage workers, most of them from poor states in India's north and east.
The Silkyara tunnel is part of Indian Prime Minister Narendra Modi’s project aimed at better connecting the famous Hindu shrines in the Uttarakhand district.
Similar accidents have occurred over the years. In January, thousands of people were evacuated from their homes in Joshimath, also located in Uttarakhand, after more than 600 houses developed cracks.
Landslides during the monsoon season in India have also caused several disasters such as the death of over 60 people in the Himalayas in August this year.