NEW DELHI — To reach the coal deposits in remote northeast India, workers dig shafts straight down into the earth, then excavate a labyrinth of narrow, horizontal tunnels. Miners work in the pitch black, hunched over, in thousands of these “rat hole” mines — every one of them illegal.

On Dec. 13, water flooded a network of tunnels in such a mine in the eastern part of Meghalaya state, trapping 15 men and prompting a rescue attempt that has grown increasingly desperate.

A month after the accident, the fate of the miners remains unknown. No blueprint exists of the tunnels, which are now filled with frigid water from the nearby Lytein river.

Last summer, when 12 boys and their soccer coach were trapped in a flooded cave in Thailand, the dramatic rescue operation riveted that nation and the world. The mining accident in Meghalaya — a thinly populated state north of Bangladesh — initially drew little attention, and the rescue effort has been plagued by delays and difficulties.

A team of Indian navy divers is at the site. But the depth of the water in the mine’s main shaft has prevented them from exploring the tunnels. The 350-foot shaft was filled halfway up with water, and despite the use of pumps, divers have been unable to operate.

“There is no substantial decrease” in the water level to date, said S.K. Singh, an assistant commandant with the National Disaster Response Force, who is part of the rescue effort. He declined to comment on the miners’ chances of survival, saying that the government is making “its best efforts” and that “we are still hopeful.”

The accident in the East Jaintia Hills district might have gone undetected were it not for a handful of survivors. One ­22-year-old told an Indian television station that the coal in the mine was “soft,” a sign of water seepage. Just as he exited with a load of coal, he said, he heard water gushing into the tunnels. “All miners knew the mine was unsafe and that water might come in any moment,” he said.

Justina Dkhar is the mother of two men from the nearby village of Lumthari who were trapped in the mine. She said her sons, ages 20 and 22, did not normally work in the coal mine but took the job to earn more money ahead of Christmas. “Now I only hope to retrieve their bodies,” Dkhar said. Her 22-year-old nephew was also among those trapped.

The situation has placed a harsh spotlight on the mining industry in Meghalaya, which draws poor migrant workers from the neighboring state of Assam. In 2014, India’s national environmental court outlawed coal mining in Meghalaya, citing a devastating increase in pollution in rivers. But the prohibition on mining appears to exist mostly on paper.

B.P. Katakey, a retired judge, led a fact-finding mission to the state last year at the order of the environmental court, known as the National Green Tribunal. His committee found that there were more than 24,000 mines in the state. During his visit, he saw piles of freshly mined coal stacked on both sides of a road.

Mine owners do “absolutely nothing” for the safety of their workers, Katakey said in an interview. Meanwhile, widespread mining has polluted the state’s rivers and rendered them acidic. In certain areas, the pH level in rivers is less than 3, Katakey said, a highly acidic reading. (The ideal pH level for drinking water is 7.)

The state administration blames a lack of manpower for its inability to enforce the mining ban. But the industry also benefits from the support of elected officials, some of whom own mines, said Patricia Mu­khim, editor of the Shillong Times, a newspaper in the state capital.

“This is the political economy of the state,” she said. “All elections are funded by coal money.” In November, two female activists who traveled to the East Jaintia Hills district to investigate illegal mining activities were attacked.

Immediately after the Dec. 13 mine flood, a local disaster management official requested help from his national counterpart. However, he framed the mission as recovering “dead bodies” rather than as a rescue attempt, according to court documents. The lack of urgency persisted for nearly two weeks, the records show.

On Dec. 25, Rahul Gandhi, the leader of India’s main opposition party, tweeted about the miners while taking a dig at Prime Minister Narendra Modi. India’s Supreme Court ordered the state government to provide regular updates on the status of the operation.

The remoteness of the mine and the depth of the shaft have hindered the rescue efforts. It was only recently that high-capacity 100-horsepower water pumps were successfully used in the mine.

More than 120 people are now at the site, including personnel from disaster management agencies and experts from a major state-controlled coal company.

But absent any signs that the miners have found an air pocket, hopes have dwindled. When Mukhim, the newspaper editor, visited the mine last month, she began to cry. “It looks very dangerous. It’s pitch dark down there,” she said. “It is a hole of death.”

Siangshai reported from Jowai, India.