Forty-one construction workers have crawled free after 17 days trapped underground in a collapsed tunnel in one of India’s “most difficult rescue missions in history”.

The men were in good health as they emerged on their hands and knees late on Tuesday (local time), after a tireless operation to drill through the debris of rock, concrete and earth enclosing them in the Himalayas.

The low-wage workers from some of India’s poorest states escaped through a 90-centimetre wide steel pipe to a crowd of flashing cameras and state government officials.

The first to be pulled out was garlanded with marigold flowers and welcomed in traditional Indian style.

Some walked out smiling and received hugs while others made gestures of thanks with clasped hands or sought blessings by touching the minister’s feet.

Pushkar Singh Dhami, chief minister of Uttarakhand state, said none of the workers were weak or feverish – “they are all healthy”.

“While there were stretchers for them to come out, they chose to come out crawling on their own,” he said.

India’s president Droupadi Murmu said on X their survival and weeks-long rescue effort was “a testament of human endurance”.

“I congratulate the teams and all experts who have acted with incredible grit and determination to perform one of the most difficult rescue missions in history.”

Ambulances that had lined up with lights flashing at the mouth of the tunnel transported the workers to a hospital about 30 kilometres away.

Local residents gathered outside the tunnel set off firecrackers, distributed sweets and shouted slogans hailing Mother India.

The 41 men had been getting food, water, light, oxygen and medicines through a pipe. But efforts to dig a tunnel to rescue them with high-powered drilling machines were frustrated by snags.

Government agencies managing the unprecedented crisis had turned to “rat miners” to drill through the rocks and gravel by hand from inside the evacuation pipe pushed through the debris after machinery failed.

The miners are experts at a primitive, hazardous and controversial method used mostly to get at coal deposits through narrow passages, and get their name because they resemble burrowing rats.

The men were working on the Silkyara tunnel in the Uttarkashi district when it collapsed. Photo: Getty

The miners, brought from central India, worked through Monday night (local time) and finally broke through the estimated 60 metres of rocks, earth and metal on Tuesday afternoon.

The tunnel is part of the $US1.5 billion ($2.3 billion) Char Dham highway, one of Prime Minister Narendra Modi’s most ambitious projects, aimed at connecting four Hindu pilgrimage sites through an 890-kilometre network of roads.

Authorities have not said what caused the cave-in but the region is prone to landslides, earthquakes and floods.

-with AAP